Prepare tests for kotlinx-coroutines-test

[ankushg]

Necessary to support test cases on the JS Target

Tests are failing on Kotlin/Native platforms.

Currently blocked by Kotlin/kotlinx.coroutines#3195

[rickclephas]

Let's see what happens with the kotlinx.coroutines issue. If it can't be fixed we can always create an expect/actual for runTest that uses runBlocking on native (at least until the old memory model with the freezing is dropped 😁)

[rickclephas]

Alright I have added a kind of hacky workaround for the freezing issue. The test are now using expect functions that are currently mapped to runBlocking in appleTest in jsTest these should be mapped to the kotlinx-coroutines-test functions.

I guess the two delays that are still in there should be replaced with a call to runCurrent as well on JS.
If that is the case then we need to add another expect function 😅.

Anyway this shouldn't be a problem for long since the whole freezing thing will be gone once the old native memory model is dropped 😁.