RFR: 8292266: Add JFR event for total Reference processing time [v2]

[Sangheon Kim]

> Hi all,
> 
> Can I have reviews for this change that adds a new JFR event for total Reference Processing time?
> 
> The goal is to generate a new JFR event if there is already measured time. This CR doesn't add new time measurement.
> 
> Testing: hs-tier1 ~ 3
> 
> Thanks,
> Sangheon

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

  Update src/hotspot/share/jfr/metadata/metadata.xml
  
  Co-authored-by: Thomas Schatzl <59967451+tschatzl at users.noreply.github.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/11230/files
  - new: https://git.openjdk.org/jdk/pull/11230/files/ec9209a5..a85df44e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11230&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11230&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11230.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11230/head:pull/11230

PR: https://git.openjdk.org/jdk/pull/11230