RFR(S): 8050973: CMS/G1 GC: add missing Resource and Handle Mark

[Lindenmaier, Goetz]

Hi,

This fixes two missing Resource and Handle marks.

Please review and test this change.  We please need a sponsor
to push it.
http://cr.openjdk.java.net/~goetz/webrevs/8050973-mark/webrev-01/

Should this be pushed to 8u20?

Thanks and best regards,
  Martin and Goetz