The root cause is that x86 has a stronger memory model than the ARM
processors. And the GCC builtins didn't issue the correct fences when
setting/unsetting the lock word. In particular during the mutex release.

The solution is rewriting atomic TAS operations: replace '__sync_' by
'__atomic_' if possible.
Reviewed-by: Sunny Bains      <sunny.bains@oracle.com>
Reviewed-by: Bin Su           <bin.x.su@oracle.com>
Reviewed-by: Debarun Banerjee <debarun.banerjee@oracle.com>
Reviewed-by: Krunal Bauskar   <krunal.bauskar@oracle.com>
RB: 9782
RB: 9665
RB: 9783