8076995: gc/ergonomics/TestDynamicNumberOfGCThreads.java failed with java.lang.RuntimeException: 'new_active_workers' missing from stdout/stderr
Reviewed-by: jmasa, drwhite

Reviewed-by: jmasa, kbarrett, tschatzl

Reviewed-by: kvn

Reviewed-by: dcubed, dsamersoff

Reviewed-by: kbarrett, tschatzl

Summary: Adding missing check for valid oop.
Reviewed-by: dcubed
Contributed-by: NShafi Ahmad <shafi.s.ahmad@oracle.com>

Reviewed-by: kvn

Reviewed-by: kvn, mdoerr

Reviewed-by: dsamersoff, dcubed

Reviewed-by: coleenp

Reviewed-by: stuefe, coleenp, roland

Summary: gcc expects clean 32 bit int in 64 bit register on function entry
Reviewed-by: kvn, dlong