Replace Environment.Exit with ProcessExitSource and cancelation token

[LukaszRozmej]

Potentially Fixes #5298

Changes

• Removes all Environment.Exit and replaces them by using wrapped cancellation token source

Types of changes

What types of changes does your code introduce?

• Bugfix (a non-breaking change that fixes an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a change that causes existing functionality not to work as expected)
• Optimization
• Refactoring
• Documentation update
• Build-related changes
• Other: Description

Testing

Requires testing

• Yes
• No

If yes, did you write tests?

• Yes
• No

[Scooletz]

One nitpick and one more important comment.

[Scooletz]

A nitpick: the CompareExchange above can be replaced with Exchange as you always get the previous value.

[LukaszRozmej]

Well depends, if someone would have swapped it for something else by then, then we could break that logic.

[LukaszRozmej]

Unfortunately didn't fix:

Test Run Aborted with error System.Exception: One or more errors occurred.
---> System.Exception: Unable to read beyond the end of the stream.
at System.IO.BinaryReader.Read7BitEncodedInt()
at System.IO.BinaryReader.ReadString()
at Microsoft.VisualStudio.TestPlatform.CommunicationUtilities.LengthPrefixCommunicationChannel.NotifyDataAvailable()
at Microsoft.VisualStudio.TestPlatform.CommunicationUtilities.TcpClientExtensions.MessageLoopAsync(TcpClient client, ICommunicationChannel channel, Action`1 errorHandler, CancellationToken cancellationToken)
--- End of inner exception stack trace ---.
Error: Process completed with exit code 1.