RFR: 8316935: [s390x] Use consistent naming for lightweight locking in MacroAssembler

[Amit Kumar]

We (s390) also needs to update our naming from fast_lock & fast_unlock to MacroAssembler::lightweight_lock and MacroAssembler::lightweight_unlock respectively.

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Commit messages:
 - s390 patch

Changes: https://git.openjdk.org/jdk/pull/15915/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15915&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316935
  Stats: 16 lines in 4 files changed: 0 ins; 0 del; 16 mod
  Patch: https://git.openjdk.org/jdk/pull/15915.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15915/head:pull/15915

PR: https://git.openjdk.org/jdk/pull/15915