MSBuild task hangs occasionally in Linux when invoking 'dotnet run'

## Steps to reproduce
Create a project, add a target that is invoked before target `BeforeBuild`. That task should then invoke ``.

## Expected behavior
I expect the command to run and finish, so that msbuild can continue executing targets.

## Actual behavior
Msbuild seemingly hangs, as if it cannot determine that `OtherProject` has exited. This only occurs in Linux, and only sometimes. It always hangs when I run the same task on the Ubuntu 1604 hosted agent in Azure DevOps. It sometimes hangs when I run the same task in Docker on my Windows desktop machine.

## Environment data
I am using the docker image `microsoft/dotnet:2.2-sdk` as a base for my own image. I have stripped it down to a bare minimum with `/bin/bash` as ENTRYPOINT, so that I have been able to run the commands manually.

`dotnet --info` output:
```
.NET Core SDK (reflecting any global.json):
Version: 2.2.104
Commit: 73f036d4ac

Runtime Environment:
OS Name: debian
OS Version: 9
OS Platform: Linux
RID: debian.9-x64
Base Path: /usr/share/dotnet/sdk/2.2.104/

Host (useful for support):
Version: 2.2.2
Commit: a4fd7b2c84

.NET Core SDKs installed:
2.2.104 [/usr/share/dotnet/sdk]

.NET Core runtimes installed:
Microsoft.AspNetCore.All 2.2.2 [/usr/share/dotnet/shared/Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.2.2 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.2.2 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

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

The "offending" target looks like this in my .csproj:
```

```

The project `Tracy.Core.Dal.ModelBuilderGenerator` is a custom project that generates code at runtime for other projects to consume. In the logs I can see all the output from the generator project. The very last output is right before `return 0;`.

The workaround I have now is to tag the target with `Condition="'$(BuildingInsideVisualStudio)' == 'true'"` so that it'll work as expected during development time. During build, I publish the tool in my Docker file to an executable, which I run before the initial `dotnet` invocation.

## Source code access
Access to source code etc can be arranged privately if needed.