RFR: 8199407: Skip Rebuild Remset Phase if there are no rebuild candidates [v4]

[Ivan Walulya]

> Hi all,
> 
> Please review this change that skips the rebuild remset phase and the associated updates after rebuild, If during Remark, G1 finds that there are no remembered sets to rebuild.
> 
> Test: tier1-5

Ivan Walulya has updated the pull request incrementally with one additional commit since the last revision:

  Update src/hotspot/share/gc/g1/g1ConcurrentMark.hpp
  
  Co-authored-by: Stefan Johansson <54407259+kstefanj at users.noreply.github.com>

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3434/files
  - new: https://git.openjdk.java.net/jdk/pull/3434/files/41744103..cbd3c47c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3434&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3434&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3434.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3434/head:pull/3434

PR: https://git.openjdk.java.net/jdk/pull/3434