Problems/error state does not update until file is modified (Mac only)

## Issue Description ##

VSCode does not report C# programming errors (problems) either inline or in the Problems pane until the file containing the problem is updated. "Updated" means either modifying the file buffer or saving the file. In other words, if a change to File B causes problems in File A, VSCode will not report the problem until File A is updated.

This issue appears to be MacOS-specific. I was able to reproduce it using both the extension's built-in Mono, as well as the global Mono (6.12.0.140). I'm running MacOS 11.6 on an M1 MacBook Air.

I was not able to reproduce this issue on my Windows machine. If you change File B such that code in File A becomes invalid, the Windows version of VSCode will immediately report problems in File A.

## Steps to Reproduce ##

1. Use the MacOS version of VSCode, with the C# extension enabled. The choice of Mono (global or built-in) does not seem to matter.
2. Check out [this example repo](https://github.com/jeffomatic/csharp-vscode-test). It's a barebones "Hello World"-style project.
3. Open `Program.cs` and `OtherClass.cs`.
4. In `OtherClass.cs`, comment out the `OtherClass.Print()` method.
5. Observe that:
- No problem is reported for the now-invalid call to `OtherClass.Print()` in `Program.cs`.
- Saving `OtherClass.cs` has no effect.
- Similar issues arise if you invalidate the callsite in other ways, such as changing `OtherClass.Print` to private, adding new parameters, renaming it, etc.
6. Save `Program.cs`.
7. Observe that:
- The call to `OtherClass.Print()` in `Program.cs` now displays (correctly) an inline problem (a red squiggle underline) as well as an entry in the Problems pane.
- As an alternative to saving `Program.cs`, typing keystrokes into `Program.cs` also causes the problem to appear.
- Interestingly, closing and opening `Program.cs` does _not_ have the same effect; it seems that you have to perform an action that causes the extension to think that the file contents have changed.

The reverse process shows similar behavior: if you uncomment `OtherClass.Print()`, the problems reported will not go away until `Program.cs` is modified again. In other words, this issue causes _both_ false positives and false negatives. In general, it appears that problems state from a file will not be reported unless the file containing invalid code is itself is touched in some way.

## Expected Behavior ##

Changes in `OtherClass.cs` should immediately cause problems to be reported in `Program.cs`. This is the behavior of pretty much every other built-in code intelligence package, including:

- VSCode/C# on Windows
- Visual Studio (both Mac and Windows)
- Rider
- TypeScript in VSCode

Having problems reported (at least in open files) as soon as changes are made are an important part of the IDE workflow. If you make a change that causes other files to become invalid, you want to know right away. This bug degrades developer experience considerably.

## Actual Behavior ##

Changes in `OtherClass.cs` that invalidate code in `Program.cs` do not trigger problems until `Program.cs` is modified or saved.

## Logs ##

### OmniSharp log ###

Starting OmniSharp server at 10/31/2021, 11:20:23 AM
Target: /Users/jefflee/src/csharp-vscode-test

OmniSharp server started.
Path: /Users/jefflee/.vscode/extensions/ms-dotnettools.csharp-1.23.16/.omnisharp/1.37.16/run
PID: 41971

[info]: OmniSharp.Stdio.Host
Starting OmniSharp on MacOS 11.6 (x64)
[info]: OmniSharp.Services.DotNetCliService
Checking the 'DOTNET_ROOT' environment variable to find a .NET SDK
[info]: OmniSharp.Services.DotNetCliService
Using the 'dotnet' on the PATH.
[info]: OmniSharp.Services.DotNetCliService
DotNetPath set to dotnet
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Located 1 MSBuild instance(s)
1: StandAlone 17.0.0 - "/Users/jefflee/.vscode/extensions/ms-dotnettools.csharp-1.23.16/.omnisharp/1.37.16/omnisharp/.msbuild/Current/Bin"
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
MSBUILD_EXE_PATH environment variable set to '/Users/jefflee/.vscode/extensions/ms-dotnettools.csharp-1.23.16/.omnisharp/1.37.16/omnisharp/.msbuild/Current/Bin/MSBuild.exe'
[info]: OmniSharp.MSBuild.Discovery.MSBuildLocator
Registered MSBuild instance: StandAlone 17.0.0 - "/Users/jefflee/.vscode/extensions/ms-dotnettools.csharp-1.23.16/.omnisharp/1.37.16/omnisharp/.msbuild/Current/Bin"
CscToolExe = csc.exe
MSBuildToolsPath = /Users/jefflee/.vscode/extensions/ms-dotnettools.csharp-1.23.16/.omnisharp/1.37.16/omnisharp/.msbuild/Current/Bin
CscToolPath = /Users/jefflee/.vscode/extensions/ms-dotnettools.csharp-1.23.16/.omnisharp/1.37.16/omnisharp/.msbuild/Current/Bin/Roslyn
BypassFrameworkInstallChecks = true
MSBuildExtensionsPath = /Users/jefflee/.vscode/extensions/ms-dotnettools.csharp-1.23.16/.omnisharp/1.37.16/omnisharp/.msbuild
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.CSharpFormattingWorkspaceOptionsProvider, Order: 0
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.Completion.CompletionOptionsProvider, Order: 0
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.RenameWorkspaceOptionsProvider, Order: 100
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.ImplementTypeWorkspaceOptionsProvider, Order: 110
[info]: OmniSharp.WorkspaceInitializer
Invoking Workspace Options Provider: OmniSharp.Roslyn.CSharp.Services.BlockStructureWorkspaceOptionsProvider, Order: 140
[info]: OmniSharp.Cake.CakeProjectSystem
Detecting Cake files in '/Users/jefflee/src/csharp-vscode-test'.
[info]: OmniSharp.Cake.CakeProjectSystem
Could not find any Cake files
[info]: OmniSharp.MSBuild.ProjectSystem
No solution files found in '/Users/jefflee/src/csharp-vscode-test'
[info]: OmniSharp.MSBuild.ProjectManager
Queue project update for '/Users/jefflee/src/csharp-vscode-test/csharp-vscode-test.csproj'
[info]: OmniSharp.Script.ScriptProjectSystem
Detecting CSX files in '/Users/jefflee/src/csharp-vscode-test'.
[info]: OmniSharp.Script.ScriptProjectSystem
Could not find any CSX files
[info]: OmniSharp.WorkspaceInitializer
Configuration finished.
[info]: OmniSharp.Stdio.Host
Omnisharp server running using Stdio at location '/Users/jefflee/src/csharp-vscode-test' on host 41925.
[info]: OmniSharp.MSBuild.ProjectManager
Loading project: /Users/jefflee/src/csharp-vscode-test/csharp-vscode-test.csproj
[info]: OmniSharp.MSBuild.ProjectManager
Successfully loaded project file '/Users/jefflee/src/csharp-vscode-test/csharp-vscode-test.csproj'.
[info]: OmniSharp.MSBuild.ProjectManager
Adding project '/Users/jefflee/src/csharp-vscode-test/csharp-vscode-test.csproj'
[info]: OmniSharp.MSBuild.ProjectManager
Update project: csharp-vscode-test
[info]: OmniSharp.Roslyn.CSharp.Services.Diagnostics.CSharpDiagnosticWorkerWithAnalyzers
Solution initialized -> queue all documents for code analysis. Initial document count: 4.
Received response for /quickinfo but could not find request.

### C# log ###
The C# log was blank.

## Environment information ##

**VSCode version**: 1.61.2
**C# Extension**: 1.23.16

Mono Information
OmniSharp using built-in mono
Dotnet Information
.NET SDK (reflecting any global.json):
Version: 5.0.400
Commit: d61950f9bf

Runtime Environment:
OS Name: Mac OS X
OS Version: 11.0
OS Platform: Darwin
RID: osx.11.0-x64
Base Path: /usr/local/share/dotnet/sdk/5.0.400/

Host (useful for support):
Version: 5.0.9
Commit: 208e377a53

.NET SDKs installed:
3.1.412 [/usr/local/share/dotnet/sdk]
5.0.301 [/usr/local/share/dotnet/sdk]
5.0.400 [/usr/local/share/dotnet/sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 3.1.18 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.7 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.9 [/usr/local/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 3.1.18 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.7 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.9 [/usr/local/share/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET runtimes or SDKs:
https://aka.ms/dotnet-download

Visual Studio Code Extensions

|Extension|Author|Version|
|---|---|---|
|csharp|ms-dotnettools|1.23.16|
|even-better-toml|tamasfe|0.14.2|
|githistory|donjayamanne|0.6.19|
|gltf-vscode|cesium|2.3.12|
|prettify-json|mohsen1|0.0.3|
|reddevil-vsc-helpers|jeffanddom-dot-com|0.0.1|
|remote-containers|ms-vscode-remote|0.202.5|
|remote-ssh|ms-vscode-remote|0.65.8|
|remote-ssh-edit|ms-vscode-remote|0.65.8|
|rewrap|stkb|1.14.0|
|ruby|rebornix|0.28.1|
|rust-analyzer|matklad|0.2.792|
|shaderlabvscode|amlovey|1.3.2|
|theme-monokai-pro-vscode|monokai|1.1.19|
|unity-debug|Unity|3.0.2|
|unity-tools|Tobiah|1.2.12|
|vscode-docker|ms-azuretools|1.17.0|
|vscode-eslint|dbaeumer|2.2.2|
|vscode-ruby|wingrunr21|0.28.0|;