NSArrayController.Remove destroys unrelated empty NSArray

### Steps to Reproduce

1. Run a project attached
2. Click a button in the main window
3. Observe that NSArray.Handle is non-zero before calling NSArrayController.Remove and became zero just after the call to Remove.

Minimal test code
```
NSArray Array = new NSArray();

var alert = new NSAlert();
alert.InformativeText = "ViewController.Array.Handle before arrayControllerUnbinded.Remove: " + Array.Handle;
alert.RunModal(); //Handle is non-zero

var controller = new NSArrayController();
controller.Remove(controller.ArrangedObjects());

alert.InformativeText = "ViewController.Array.Handle after arrayControllerUnbinded.Remove: " + Array.Handle;
alert.RunModal(); //Handle is zero
```

### Expected Behavior
Operations with NSArrayController do not affect any objects, which is not related to this array controller.

### Actual Behavior
Calling NSArrayController.Remove leads to unrelated NSArray being destroyed (NSArray.Handle=0).

### Additional details
There is NSArray local variable in the button handler and NSArrayController. The NSArray variable is initialised with an empty NSArray. The Array controller do not have any bindings and other connections, so it is completely unrelated to the NSArray variable mentioned above.
The button handler calls Remove on the ArrayController in form of
` arrayControllerUnbinded.Remove(arrayControllerUnbinded.ArrangedObjects());
`
After this call the NSArray variable Handle become zero.

Some additional notes
* the NSArray may be a local variable, field or property (with or without Export attribute) - the problem is observed in all cases.
* the NSArray and NSArrayController may be in the different classes/xibs - the problem will still persist
* the problem does *not* observed if the NSArray is not empty
* the problem does *not* observed for NSMutableArray (whatever empty or not)

### Environment

```
=== Visual Studio Community 2019 for Mac ===

Version 8.6.2 (build 6)
Installation UUID: 106edc06-c1ac-4a89-9783-ea18c79458d1
GTK+ 2.24.23 (Raleigh theme)
Xamarin.Mac 6.18.0.23 (d16-6 / 088c73638)

Package version: 612000090

=== Mono Framework MDK ===

Runtime:
Mono 6.12.0.90 (2020-02/d3daacdaa80) (64-bit)
Package version: 612000090

=== Roslyn (Language Service) ===

3.6.0-3.20210.9+4eafdcb1bcbd8d3573f2ba6065e56d9b9ce4f8a3

=== NuGet ===

Version: 5.6.0.6591

=== .NET Core SDK ===

SDK: /usr/local/share/dotnet/sdk/3.1.401/Sdks
SDK Versions:
3.1.401
3.1.302
MSBuild SDKs: /Library/Frameworks/Mono.framework/Versions/6.12.0/lib/mono/msbuild/Current/bin/Sdks

=== .NET Core Runtime ===

Runtime: /usr/local/share/dotnet/dotnet
Runtime Versions:
3.1.7
3.1.6
2.1.21
2.1.20

=== Xamarin.Profiler ===

Version: 1.6.15.68
Location: /Applications/Xamarin Profiler.app/Contents/MacOS/Xamarin Profiler

=== Updater ===

Version: 11

=== Apple Developer Tools ===

Xcode 11.7 (16142)
Build 11E801a

=== Xamarin.Mac ===

Version: 6.20.2.2 (Visual Studio Community)
Hash: 817b6f72a
Branch: d16-7
Build date: 2020-07-18 18:44:59-0400

=== Xamarin.iOS ===

Xamarin.iOS not installed.
Can't find mtouch or the Version file at /Library/Frameworks/Xamarin.iOS.framework/Versions/Current.

=== Xamarin Designer ===

Version: 16.6.0.329
Hash: d4f8bcd13
Branch: remotes/origin/d16-6
Build date: 2020-04-24 02:16:02 UTC

=== Xamarin.Android ===

Not Installed

=== Microsoft Mobile OpenJDK ===

Java SDK: Not Found

Android Designer EPL code available here:
https://github.com/xamarin/AndroidDesigner.EPL

=== Android SDK Manager ===

Version: 16.6.0.50
Hash: 5901879
Branch: remotes/origin/d16-6
Build date: 2020-04-30 04:01:22 UTC

=== Android Device Manager ===

Version: 16.6.0.95
Hash: 45d17b5
Branch: remotes/origin/d16-6
Build date: 2020-04-30 04:01:42 UTC

=== Build Information ===

Release ID: 806020006
Git revision: c742dc3fcbf76855738eef57ce41d65f91acbf27
Build date: 2020-05-28 15:22:51-04
Build branch: release-8.6
Xamarin extensions: c742dc3fcbf76855738eef57ce41d65f91acbf27

=== Operating System ===

Mac OS X 10.15.6
Darwin 19.6.0 Darwin Kernel Version 19.6.0
Thu Jun 18 20:49:00 PDT 2020
root:xnu-6153.141.1~1/RELEASE_X86_64 x86_64

=== Enabled user installed extensions ===

FileNesting 0.1.2

```

### Build Logs

Build log

Building 44 (Debug)
Build started 07.09.2020 17:22:03.
__________________________________________________
Project "/Users/sergey/work/44/44/44.csproj" (Build target(s)):

Target _BeforeCoreCompileImageAssets:
Skipping target "_BeforeCoreCompileImageAssets" because all output files are up-to-date with respect to the input files.
Target _CoreCompileImageAssets:
Skipping target "_CoreCompileImageAssets" because all output files are up-to-date with respect to the input files.
Target _CoreCompileInterfaceDefinitions:
BundleResources Output:
obj/Debug/ibtool/Main.storyboardc/MainMenu.nib
obj/Debug/ibtool/Main.storyboardc/XfG-lQ-9wD-view-m2S-Jp-Qdl.nib
obj/Debug/ibtool/Main.storyboardc/NSWindowController-B8D-0N-5wS.nib
obj/Debug/ibtool/Main.storyboardc/Info.plist
OutputManifests Output:
obj/Debug/ibtool-manifests/Main.storyboardc
Target _CoreCompileColladaAssets:
Skipping target "_CoreCompileColladaAssets" because it has no inputs.
Target GenerateTargetFrameworkMonikerAttribute:
Skipping target "GenerateTargetFrameworkMonikerAttribute" because all output files are up-to-date with respect to the input files.
Target CoreCompile:
/Library/Frameworks/Mono.framework/Versions/6.12.0/lib/mono/msbuild/Current/bin/Roslyn/csc.exe /noconfig /nowarn:1701,1702,2008 /nostdlib+ /errorreport:prompt /warn:4 /define:__UNIFIED__;__MACOS__;DEBUG /errorendlocation /preferreduilang:en-US /reference:/Library/Frameworks/Xamarin.Mac.framework/Versions/Current/lib/mono/Xamarin.Mac/mscorlib.dll /reference:/Library/Frameworks/Xamarin.Mac.framework/Versions/Current/lib/mono/Xamarin.Mac/System.Core.dll /reference:/Library/Frameworks/Xamarin.Mac.framework/Versions/Current/lib/mono/Xamarin.Mac/System.dll /reference:/Library/Frameworks/Xamarin.Mac.framework/Versions/Current/lib/mono/Xamarin.Mac/Facades/System.Drawing.Common.dll /reference:/Library/Frameworks/Xamarin.Mac.framework/Versions/Current/lib/mono/Xamarin.Mac/Xamarin.Mac.dll /debug+ /debug:full /optimize- /out:obj/Debug/44.exe /target:exe /utf8output /langversion:7.3 Main.cs AppDelegate.cs ViewController.cs ViewController.designer.cs "obj/Debug/Xamarin.Mac,Version=v2.0.AssemblyAttributes.cs"
Using shared compilation with compiler from directory: /Library/Frameworks/Mono.framework/Versions/6.12.0/lib/mono/msbuild/Current/bin/Roslyn
Target CopyFilesToOutputDirectory:
Copying file from "/Users/sergey/work/44/44/obj/Debug/44.exe" to "/Users/sergey/work/44/44/bin/Debug/44.exe".
44 -> /Users/sergey/work/44/44/bin/Debug/44.exe
Copying file from "/Users/sergey/work/44/44/obj/Debug/44.pdb" to "/Users/sergey/work/44/44/bin/Debug/44.pdb".
Target _DetectSigningIdentity:
Detected signing identity:

Bundle Id: com.companyname.x44
App Id: com.companyname.x44
Target _CopyContentToBundle:
Skipping target "_CopyContentToBundle" because all output files are up-to-date with respect to the input files.
Target _CompileAppManifest:
Skipping target "_CompileAppManifest" because all output files are up-to-date with respect to the input files.
Target _CompileToNative:
/Library/Frameworks/Xamarin.Mac.framework/Versions/Current/bin/mmp @/Users/sergey/work/44/44/obj/Debug/response-file.rsp

Build succeeded.
0 Warning(s)
0 Error(s)

Time Elapsed 00:00:06.53

========== Build: 1 succeeded, 0 failed, 0 up-to-date, 0 skipped ==========

Build successful.

### Example Project (If Possible)

[44.zip](https://github.com/xamarin/xamarin-macios/files/5182568/44.zip)