RFR: 8277411: C2 fast_unlock intrinsic on AArch64 has unnecessary ownership check

[Erik Österlund]

The AArch64 fast_unlock C2 code checks if the current thread owns the lock. This can be surprisingly expensive in workload where locking is contended. The check is however optional (helpful only for finding JNI code bugs), and indeed not emitted for x86_64. This patch removes the check on AArch64 as well.

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Commit messages:
 - 8277411: C2 fast_unlock intrinsic on AArch64 has unnecessary ownership check

Changes: https://git.openjdk.java.net/jdk/pull/6498/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6498&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8277411
  Stats: 5 lines in 1 file changed: 0 ins; 4 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6498.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6498/head:pull/6498

PR: https://git.openjdk.java.net/jdk/pull/6498