Cancelling TestContext on non [Timeout] [TestMethod] should still cancel test

[Evangelink]

Description

With current implementation, the CancellationTokenSource property of the TestContext always allows you to cancel a test but if the [TestMethod] is not marked with [Timeout] nothing will happen. This seems like a confusing behavior and as a user I would expect that my manual cancellation request is honored.

AB#2050315

[testplatform-bot]

✅ Successfully linked to Azure Boards work item(s):

• User Story 2050315

[Evangelink]

After some discussions and tests, the feature doesn't make much sense. For a user to call Cancel on the token of the TestContext that means we are already in the user code so they could simply return or throw. There is also no need to start a different thread and stop observing it (as we do for timeout) because once again the user is in control and can exit the method execution so they are never blocked.

For these reasons we decided not to implement this feature.