New test-run request should cancel any in-process test runs to begin the new test-run immediately

[MahdiBM]

Describe the bug
Like in Xcode, when you hit the "test run" button, if there exists a running test-run, the old test-run should be immediately cancelled so the new test-run can begin.

To Reproduce
Steps to reproduce the behavior:

• Run a long-running test.
• Hit the run-test button again.
• Observe the second test-run request does nothing, at least until the first test is over.

Expected behavior
Explained above.

Environment
Doesn't matter.

Additional context
Add any other context about the problem here.

[award999]

That is what the cancel test run button provided by VSCode does. Maybe one day VSCode will come up with similar logic as debug sessions where they ask the user if they want to cancel since they are managing the cancellation tokens

[MahdiBM]

Hmm what about the extension at least letting users know that there is an existing test going on and that they need ro cancel that first?