[crac] RFR: Support updating MANAGEABLE JVM options during restore [v5]

[Radim Vansa]

> When a JVM option is MANAGEABLE it can be set at any time during runtime, therefore it is safe to change it during the restore operation. Rather than silently ignoring JVM options passed along with -XX:CRaCRestoreFrom we send them to the restored process and either update or print a warning if given option cannot be changed.

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

 - Merge branch 'crac' into vmoptions
 - Make CRTrace RESTORE_SETTABLE rather than MANAGEABLE
 - Fixup
 - Use RESTORE_SETTABLE on JVM flags
   
   * Fail early when using non settable flags
   * CracBuilder fix: don't use classpath during restore
 - Support updating MANAGEABLE JVM options during restore
   
   When a JVM option is MANAGEABLE it can be set at any time during runtime, therefore it is safe to change it during the restore operation. Rather than silently ignoring JVM options passed along with -XX:CRaCRestoreFrom we send them to the restored process and either update or print a warning if given option cannot be changed.

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Changes: https://git.openjdk.org/crac/pull/61/files
 Webrev: https://webrevs.openjdk.org/?repo=crac&pr=61&range=04
  Stats: 254 lines in 12 files changed: 190 ins; 10 del; 54 mod
  Patch: https://git.openjdk.org/crac/pull/61.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/61/head:pull/61

PR: https://git.openjdk.org/crac/pull/61