RFR: 8280375: G1: Tighten mem region limit in G1RebuildRemSetHeapRegionClosure [v2]

[Hamlin Li]

> Currently, it uses `hr->end()` to guard the mem scan limit, but it should be top instead of end.

Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:

  Thomas review

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7154/files
  - new: https://git.openjdk.java.net/jdk/pull/7154/files/aa2f6565..e3c5efe9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7154&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7154&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7154.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7154/head:pull/7154

PR: https://git.openjdk.java.net/jdk/pull/7154