CI unit tests slow and/or skipped

[SimonMarquis]

Expected Behavior

The CI test suite should run fairly quickly.

Current Behavior

• io.mockk.it.ParallelTest#test() takes ~2min 37s
  It was introduced in 6aa4827 and the repeat(500) { verify {...} } is what takes the majority of its time.
  Do we need this many iterations (30 parallels of 500 calls) to test the right behavior? And could it be tested differently?
• io.mockk.it.ProxyWeakReferenceTest#test() is always skipped on CI, but fails locally.
  It currently draws ~20G of heap space to run with the current configuration 🤯
  The test tries to allocate ByteArray(10 * 1024 * 1024) (10MiB) * 1000.
  Allocating this many ByteArray should not be an issue, and actually, replacing the spyked call with something else correctly GC. This certainly means there is a memory leak happening from the spyk method call!

References:

• Spyk'ed object can't be unmocked which leads to OutOfMemoryError #1013 (comment)

[SimonMarquis]

The GC root of these spyk objects:

[SimonMarquis]

Not sure why exactly, but reverting this commit fc4b0c5 seems to make this test pass correctly (although JvmMockKProxyMakerTest#garbageCollectedProxy() now fails with MockKAgentException: Value for this result is not assigned)

[milgner]

Seeing the same behaviour on my system. While working on a potential fix for #1170 I found myself unable to run the full test suite on my system without running into OutOfMemoryError. Then I reverted the commit as suggested by @SimonMarquis and the tests passed.