[8u] RFR (S) 8223177: Data race on JvmtiEnvBase::_tag_map in double-checked locking

[Aleksey Shipilev]

Original bug:
  https://bugs.openjdk.java.net/browse/JDK-8223177
  https://hg.openjdk.java.net/jdk/jdk/rev/27c8a2e0b0e5

This patch applies to 8u, but does not compile, because regular OrderAccess methods do not accept
pointers. We need to use the *_ptr_* versions of the same methods and do casts from void*.

8u webrev:
  http://cr.openjdk.java.net/~shade/8223177/webrev.8u.01/

Testing: tier1

-- 
Thanks,
-Aleksey