RFR: A couple of minor cleanups

[Zhengyu Gu]

Just a couple of cleanups on my list for a while.

- Removed obsoleted parameter
- Unnecessary ResourceMark, where it allocates C_HEAP object.

http://cr.openjdk.java.net/~zgu/shenandoah/sh-code-cleanup/webrev.00/

Test:
   hotspot_gc_shenandoah fastdebug


Thanks,

-Zhengyu