RFR: 8374145: Remove legacy locking remnants from markWord

[Stefan Karlsson]

There's a bunch of unused code in markWord that used to be used by the removed legacy locking. I propose that we remove it.

There's a Shenandoah change that should be checked closer. My thinking is:
 `is_being_inflated`: always returns false
 `has_displaced_mark_helper`: Only returns true if both these are true:
   * `!UseCompactObjectTable` - there's an early return for this earlier in the function.
   * `lockbits == monitor_value` - checked in the if-statement above

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Commit messages:
 - 8374145: Remove legacy locking remnants from markWord

Changes: https://git.openjdk.org/jdk/pull/28927/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28927&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8374145
  Stats: 33 lines in 2 files changed: 0 ins; 32 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/28927.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28927/head:pull/28927

PR: https://git.openjdk.org/jdk/pull/28927