CTRLPlusCCancellationTokenSource doesn't cancel current TestRun

[AliveDevil]

Describe the bug

When using TestContext.CancellationTokenSource.Token.Register one cannot cancel the current test run by using the CTRLPlusCCancellationTokenSource.

Steps To Reproduce

[TestClass]
public class CancelTest
{
	public TestContext TestContext { get; set; } = default!;

	[TestMethod]
	public void TestA()
	{
		ManualResetEventSlim waitHandle = new(false);

		waitHandle.Wait(TestContext.CancellationTokenSource.Token);
	}

	[TestMethod]
	public async Task TestB()
	{
		await Task.Delay(Timeout.Infinite, TestContext.CancellationTokenSource.Token);
	}
}

Expected behavior

Ctrl-C should cancel current TestRun.

Actual behavior

Ctrl-C doesn't cancel current TestRun.

Additional context

Repro: testfx.zip

AB#2200945