[crac] RFR: 8350088: [CRaC] Stop & restart JFR recording on checkpoint [v5]

[Radim Vansa]

> All JFR recordings are closed during checkpoint. After restore JDK starts new recordings with the same parameters as those running before checkpoint.
> The recordings dumped before checkpoint are moved to a different path (`xxx.jfr` -> `xxx.<N>.jfr`, `xxx` -> `xxx.<N>` with `<N>` between 0 and 20 by default). 
> If `-XX:StartFlightRecorder=...` is passed on restore a new recording is started.

Radim Vansa has updated the pull request incrementally with one additional commit since the last revision:

  Backup existing recordings

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Changes:
  - all: https://git.openjdk.org/crac/pull/203/files
  - new: https://git.openjdk.org/crac/pull/203/files/53565e15..f6ade5f9

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=203&range=04
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=203&range=03-04

  Stats: 38 lines in 1 file changed: 37 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/crac/pull/203.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/203/head:pull/203

PR: https://git.openjdk.org/crac/pull/203