RFR: Merge lworld

[Vicente Romero]

Merge branch 'lworld' into jep_401_javac_merge_lworld

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Commit messages:
 - Merge branch 'lworld' into jep_401_javac_merge_lworld
 - 8325546: [lworld] Missing barrier in C1 compiled code on AArch64
 - 8325417: [lworld] Incorrect re-execution state at uncommon traps emitted by acmp
 - 8324114: [lworld] GTestWrapper.java fails with "assert(LockingMode == LM_LEGACY) failed: should only be called with legacy stack locking"
 - 8325343: [lworld] java/lang/reflect/Proxy/ClassRestrictions.java fails with NPE
 - 8325398: [lworld] C1 should not patch null restricted field stores
 - 8324117: [lworld] C1 hits "Can not patch access to flat field" assert after JDK-8320437
 - [lworld] More problem listing
 - [lworld] Problem listing ctw test triggering 8321734
 - [lworld] Problem listing failing javac tests
 - ... and 2 more: https://git.openjdk.org/valhalla/compare/c518a142...c5856021

The merge commit only contains trivial merges, so no merge-specific webrevs have been generated.

Changes: https://git.openjdk.org/valhalla/pull/1003/files
  Stats: 12999 lines in 146 files changed: 1916 ins; 6081 del; 5002 mod
  Patch: https://git.openjdk.org/valhalla/pull/1003.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1003/head:pull/1003

PR: https://git.openjdk.org/valhalla/pull/1003