Summary: Update the HS17 build number to 04
Reviewed-by: jcoomes

Reviewed-by: tonyp, ysr

Summary: Removed the assert: UseSerialGC is not necessarily always set when serial gc is being used.
Reviewed-by: jcoomes, jmasa, tonyp

6889757: G1: enable card mark elision for initializing writes from compiled code (ReduceInitialCardMarks)
Summary: Defer the (compiler-elided) card-mark upon a slow-path allocation until after the store  and before the next subsequent safepoint; G1 now answers yes to can_elide_tlab_write_barriers().
Reviewed-by: jcoomes, kvn, never

Summary: Restore original null checks.
Reviewed-by: never, cfang