[lworld] RFR: 8328682: [lworld] Missing barrier after value object construction

[Tobias Hartmann]

Added a missing barrier after value object construction and fixed some unrelated tests.

Thanks,
Tobias

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Commit messages:
 - 8328682: [lworld] Missing barrier after value object construction

Changes: https://git.openjdk.org/valhalla/pull/1054/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1054&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8328682
  Stats: 156 lines in 16 files changed: 76 ins; 5 del; 75 mod
  Patch: https://git.openjdk.org/valhalla/pull/1054.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1054/head:pull/1054

PR: https://git.openjdk.org/valhalla/pull/1054