RFR: JDK-8259372: remove AIX related USE_LIBRARY_BASED_TLS_ONLY and THREAD_LOCAL special handling

Thu Jan 7 16:26:13 UTC 2021

AIX 5.3 had buggy __thread support (see JDK-8176442).
That's why we introduced a macro USE_LIBRARY_BASED_TLS_ONLY and set it only to 1 on AIX (different to the other platforms supported by the OpenJDK).
However AIX 5.3 support was removed some time ago (currently we have a minimum requirement of AIX 7.X ) so the whole USE_LIBRARY_BASED_TLS_ONLY related coding could be removed.

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Commit messages:
 - JDK-8259372

Changes: https://git.openjdk.java.net/jdk/pull/1976/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1976&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259372
  Stats: 20 lines in 3 files changed: 0 ins; 17 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1976.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1976/head:pull/1976

PR: https://git.openjdk.java.net/jdk/pull/1976