RFR: 8365191: Cleanup after removing LockingMode related code [v2]

[Fredrik Bredberg]

> This is a general cleanup after removing `LockingMode` related code.
> It's a sub-task of [JDK-8344261](https://bugs.openjdk.org/browse/JDK-8344261).
> It includes:
> - Removing asserts that are no longer necessary, since we removed legacy locking and monitor locking.
> - Removing or rewriting comments, arguments or functions that are related to displaced headers.
> - Remove "always true" parameter from `MonitorExitStub`.
> - Re-type/name metadata in `BasicLock`.
> 
> Tier1-5 passes okay on supported platforms.
> 
> All other platforms (arm, ppc, riscv and s390) has been sanity checked using Qemu.

Fredrik Bredberg has updated the pull request incrementally with one additional commit since the last revision:

  Update after review

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27448/files
  - new: https://git.openjdk.org/jdk/pull/27448/files/b5d57851..85457638

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27448&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27448&range=00-01

  Stats: 3 lines in 2 files changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27448.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27448/head:pull/27448

PR: https://git.openjdk.org/jdk/pull/27448