[8u] RFR (S) 8151539: Remove duplicate AlwaysTrueClosures

[Aleksey Shipilev]

Original RFE:
  https://bugs.openjdk.java.net/browse/JDK-8151539

Original fix:
  http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/be3ffb6d8eb0

I would like to backport this cleanup to 8u, because it unblocks the Shenandoah backport in
downstream repository. Patch does not apply cleanly, because reshuffles are needed, and then some
near code is not matching the version from 9 (mostly due to Unified Logging).

8u webrev:
  http://cr.openjdk.java.net/~shade/8151539/webrev.8u.01/

Testing: Linux x86_64 {fastdebug,release} builds; all hotspot jtregs

-- 
Thanks,
-Aleksey