Using runTest instead of runBlocking for Kotlin suspend method implementation

[amitojduggal]

Hello team,

First of all, big thanks for adding support for Kotlin suspend functions in Junit 6. We have been looking forward to this.

One question: Is there a reason we are not using runTest in the implementation instead of runBlocking?
https://github.com/junit-team/junit-framework/pull/4530/files

As runTest would support virtual timers.

[marcphilipp]

My original thoughts around this: #1914 (comment)

I've just reopened #4768 to continue the discussion. I think documenting how to use runTest would be sufficient.