Address checker tests around inline cache and the baseline compiler.

I failed to repro b/147094528 locally, but there are known two sources
of inline cache noises introduced by the baseline compiler:
- ensureJitCompiled doesn't ensure the method is compile 'optimized'.
  That's what the tests expect.
- when the GC is marking, we can potentially create duplicate entries of
  the same class in the inline cache.

Bug: 147094528
Test: test.py
Change-Id: I5cd6e5874b2c7b3273a9f4c8cb0fca59263da034
5 files changed