[11u] RFR 8209186: Rename SimpleThresholdPolicy to TieredThresholdPolicy

[Aleksey Shipilev]

Original RFE:
  https://bugs.openjdk.java.net/browse/JDK-8209186
  http://hg.openjdk.java.net/jdk/jdk/rev/f32e61253792

Patch does not apply to 11u cleanly, because JDK-8222670 backport went in first. This actually
highlights the benefit for making the rename early, to fit any future backports (notably JDK-8076988
and JDK-8216375).

So, I had to recreate the patch by hand. As in original patch, we move .inline.hpp into .cpp, along
with includes. Then we rename SimpleThresholdPolicy -> TieredThresholdPolicy.

11u webrev:
  http://cr.openjdk.java.net/~shade/8209186/webrev.11u.01/

Testing: tier1

-- 
Thanks,
-Aleksey