[jdk16] RFR: 8257621: JFR StringPool misses cached items across consecutive recordings [v4]

[Markus Grönlund]

> Greetings,
> 
> this change fixes problems with the StringPool as it relates to chunk rotations.
> 
> Thanks
> Markus

Markus Grönlund has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains five commits:

 - fallback on incorrect generation is the EventWriter notification
 - whitespace
 - rephrasing
 - javadoc update
 - Reintroduce string pool generation

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Changes: https://git.openjdk.java.net/jdk16/pull/18/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk16&pr=18&range=03
  Stats: 193 lines in 13 files changed: 80 ins; 59 del; 54 mod
  Patch: https://git.openjdk.java.net/jdk16/pull/18.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16 pull/18/head:pull/18

PR: https://git.openjdk.java.net/jdk16/pull/18