[crac] RFR: Fix ordering of invocation on Resources

[Radim Vansa]

* When Context.beforeCheckpoint throws, invoke Context.afterRestore anyway (otherwise some resources stay in suspended state).
* Handle Resource.beforeCheckpoint triggering a registration of another resource ** Do not cause deadlock when registering from another thread ** Global resource can register JDKResource
** JDKResource can register resource with higher priority ** Other registrations are prohibited

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Commit messages:
 - Fix ordering of invocation on Resources

Changes: https://git.openjdk.org/crac/pull/60/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=60&range=00
  Stats: 584 lines in 8 files changed: 376 ins; 165 del; 43 mod
  Patch: https://git.openjdk.org/crac/pull/60.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/60/head:pull/60

PR: https://git.openjdk.org/crac/pull/60