Summary: Enabled full verification for humongous regions. Also made sure that the VerifyAfterGC works with deferred updates and G1HRRSFlushLogBuffersOnVerify.
Reviewed-by: tonyp

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