[lilliput-jdk17u:lilliput] RFR: 8317262: LockStack::contains(oop) fails "assert(t->is_Java_thread()) failed: incorrect cast to JavaThread"

[Roman Kennke]

Backports a bugfix related to lightweight locking and prepares for subsequent backport.

Not clean, but only very minor differences (e.g. the cast to JavaThread*)

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Commit messages:
 - 8317262: LockStack::contains(oop) fails "assert(t->is_Java_thread()) failed: incorrect cast to JavaThread"

Changes: https://git.openjdk.org/lilliput-jdk17u/pull/75/files
  Webrev: https://webrevs.openjdk.org/?repo=lilliput-jdk17u&pr=75&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8317262
  Stats: 100 lines in 2 files changed: 96 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/lilliput-jdk17u/pull/75.diff
  Fetch: git fetch https://git.openjdk.org/lilliput-jdk17u.git pull/75/head:pull/75

PR: https://git.openjdk.org/lilliput-jdk17u/pull/75