review (S) for 7028374: race in fix_oop_relocations for scavengeable nmethods

[Tom Rodriguez]

http://cr.openjdk.java.net/~never/7028374

7028374: race in fix_oop_relocations for scavengeable nmethods
Reviewed-by:

In ScavengeRootsInCode mode oops could sometimes be udpated after
their relocations had been updated, resulting in stale oops in
generated code.  The fix is to move the rewriting of the relocations
to the epilogue part of the scavenge nmethods logic.  I also added
verification of the CodeCache which would have detected this problem
immediately.  The statics in Class changes will be laid on top of
these changes.  Tested with statics changes with jbb.