Summary: First mercurial integration of the code for the Garbage-First garbage collector.
Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr

Summary: Compressed oops in instances, arrays, and headers. Code contributors are coleenp, phh, never, swamyv
Reviewed-by: jmasa, kamg, acorn, tbell, kvn, rasbold

Summary: Default values set by cms ergonomics are set with FLAG_SET_DEFAULT so down stream the values look like the default values and affect how later parameters are set.  Set these values with FLAG_SET_ERGO instead and adjust how later parameters are interpreted.
Reviewed-by: iveresov, apetrusenko, pbk, ysr