8159978: Use an array to store the collection set regions instead of linking through regions
Summary: Fix a potential problem with memory visibility in the sampling thread in the collection set by changing the way we store the collection set.
Reviewed-by: ehelin, jmasa
8160739: quarantine tests failing due to -XX:TieredStopAtLevel=1
8160743: quarantine tests that can't attach symbolicator to the process on MacOS X
Reviewed-by: sspitsyn, dholmes, kvn