RFR: 8252835: Revert fix for JDK-8246051

[Wang Zhuo]

Reverting JDK-8246051(SIGBUS by unaligned Unsafe compare_and_swap) because it may cause some
runtime issues.

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Commit messages:
 - 8252835:Revert fix for JDK-8246051

Changes: https://git.openjdk.java.net/jdk/pull/297/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=297&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8252835
  Stats: 83 lines in 2 files changed: 0 ins; 83 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/297.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/297/head:pull/297

PR: https://git.openjdk.java.net/jdk/pull/297