review for 7043040: JSR292: JRuby bench/shootout/binarytrees.ruby-2.ruby SEGV: constantPoolKlass::oop_follow_contents

[Tom Rodriguez]

http://cr.openjdk.java.net/~never/7043040

7043040: JSR292: JRuby bench/shootout/binarytrees.ruby-2.ruby SEGV: constantPoolKlass::oop_follow_contents
Reviewed-by:

The logic in oop_push_constants was skipping JVM_CONSTANT_Object
entries which would cause corruption in later GCs.  The fix is to use
is_pointer_entry to identify roots like all the other visitor.  The
verify_on method was also too weak so it missed the problem when run
with the verify GC flags.  Tested with failing test from report.