RFR: 8354310: JFR: Inconsistent metadata in ZPageAllocation [v2]

[Joel Sikström]

> Hello,
> 
> This PR fixes JFR metadata for ZPageAllocation after [JDK-8350441](https://bugs.openjdk.org/browse/JDK-8350441).

Joel Sikström has updated the pull request incrementally with one additional commit since the last revision:

  stefank feedback

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Changes:
  - all: https://git.openjdk.org/jdk/pull/24578/files
  - new: https://git.openjdk.org/jdk/pull/24578/files/a99cb2ef..ae724496

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24578&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24578&range=00-01

  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/24578.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24578/head:pull/24578

PR: https://git.openjdk.org/jdk/pull/24578