RemoteExecutor does not work with 32bit .NET Framework

[antonfirsov]

There is a leftover from #1376 / #1659, since RemoteExecutor does not work with dotnet xunit:

ImageSharp/tests/ImageSharp.Tests/TestUtilities/Tests/TestEnvironmentTests.cs

Lines 118 to 123 in 255802c

	// RemoteExecutor does not work with "dotnet xunit" used to run tests on 32 bit .NET Framework:
	// https://github.com/SixLabors/ImageSharp/blob/381dff8640b721a34b1227c970fcf6ad6c5e3e72/ci-test.ps1#L30
	public static bool IsNot32BitNetFramework = !TestEnvironment.IsFramework || TestEnvironment.Is64BitProcess;
	[ConditionalFact(nameof(IsNot32BitNetFramework))]
	public void RemoteExecutor_FailingRemoteTestShouldFailLocalTest()

This means that RemoteExecutor/FeatureTestRunner test passes can be false positives on 32 bit .NET Framework. Ideally this should be addressed together with #1386 by replacing dotnet xunit with a local 32bit SDK installation + build + test run.

[JimBobSquarePants]

We can close this now since we no longer support .NET Framework