RFR: 8292265: Add old gen used field at G1HeapSummary JFR event. [v2]

[Sangheon Kim]

> Hi all,
> 
> Can I have reviews for this change which adds 'old gen used' field at existing G1HeapSummary event?
> 
> Testing: tier1 ~ tier3
> 
> Thanks,
> Sangheon

Sangheon Kim has updated the pull request incrementally with one additional commit since the last revision:

  Thomas review

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11303/files
  - new: https://git.openjdk.org/jdk/pull/11303/files/5c8c1d35..85a4ac3a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11303&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11303&range=00-01

  Stats: 7 lines in 1 file changed: 1 ins; 2 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/11303.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11303/head:pull/11303

PR: https://git.openjdk.org/jdk/pull/11303