[lworld] RFR: 8334729: [lworld] CDS should no force the computation of identity hash code for value instances

[Frederic Parain]

Simple fix to prevent the VM thread from calling back to Java code when archiving value instances.

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Commit messages:
 - Prevent CDS code from calling Java code from VM thread

Changes: https://git.openjdk.org/valhalla/pull/1144/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1144&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8334729
  Stats: 3 lines in 1 file changed: 2 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/valhalla/pull/1144.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1144/head:pull/1144

PR: https://git.openjdk.org/valhalla/pull/1144