Summary: Make RedefineClasses() interoperate better with class sharing.
Reviewed-by: sspitsyn, jmasa

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

Summary: Reduce the amount of related code replication and improve pretty printing.
Reviewed-by: jmasa

Summary: Deal more gracefully with situations where C-heap scratch space cannot be had
Reviewed-by: jmasa

Summary: Backed out part of cahnge for 6624765 because of nightly testing regressions.  Reviewers below were for 6624765.
Reviewed-by: ysr, apetrusenko

Summary: In verification take into account partial coverage of a region by a card and expansion of the card table.
Reviewed-by: ysr, apetrusenko

Summary: Disable parallel reference processing when there are no worker threads
Reviewed-by: apetrusenko, pbk, jmasa, tonyp

Summary: Revert back to using the default page size for the card table
Reviewed-by: pbk, phh