Merge

7172279: G1: Clean up TraceGen0Time and TraceGen1Time data gathering Summary: Simplify code, remove unused code, remove ExitAfterGCNum Reviewed-by: huntch, johnc

7158682: G1: Handle leak when running nsk.sysdict tests Summary: Place HandleMarks in the code that allocates handles for the pending list lock so that the handles are freed and multiple, unsuccessful, attempts to schedule a GC do not cause an OOM. Reviewed-by: brutisso