[crac] RFR: 8369566: CRaC: Record metrics during checkpoint [v7]

[Radim Vansa]

> CRaC Engine can support storing additional metadata about the image. This can help the infrastructure to further refine the set of feasible images (constrained by CPU architecture and features) and select the image that is expected to perform best.

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

  Add README, truncate metric name, expose jdk.crac.internalResources

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Changes:
  - all: https://git.openjdk.org/crac/pull/269/files
  - new: https://git.openjdk.org/crac/pull/269/files/69cb1585..2ebee46b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=269&range=06
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=269&range=05-06

  Stats: 84 lines in 7 files changed: 67 ins; 5 del; 12 mod
  Patch: https://git.openjdk.org/crac/pull/269.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/269/head:pull/269

PR: https://git.openjdk.org/crac/pull/269