RFR (S): 8055358: G1: Clean up usages of heap_region_containing (8u40 backport)

[Thomas Schatzl]

Hi all,

  can I have reviews for the following backport of 8040722 to 8u40? It
helps merging the 

There were two merge errors:

- in g1OopClosures.inline.hpp,
G1UpdateRSOrPushRefOopClosure::do_oop_nv() did not apply because of some
typo fixes in a comment.

- in heapRegionSeq.inline.hpp, HeapRegionSeq::addr_to_region_unsafe()
changes did not apply because of include changes.

Webrev:
http://cr.openjdk.java.net/~tschatzl/8040722/webrev/

Original webrev:
http://cr.openjdk.java.net/~brutisso/8040722/webrev.03/

Thanks,
  Thomas