RFR 8214821: Remove ConcurrentHashTable::get_copy

[Gerard Ziemski]

Hi all,

Please review this simple fix that removes “ConcurrentHashTable::get_copy” API, whose only client was a single gtest. Doing so allows us to remove CONFIG::notfound()

That gtest replaces the usage of “get_copy” API with a local “cht_get_copy” method, which itself is implemented using "ConcurrentHashTable::get” API

I also took this opportunity to clean up a few method names in the test a bit.

References:

https://bugs.openjdk.java.net/browse/JDK-8214821
http://cr.openjdk.java.net/~gziemski/8214821_rev1

Passes gtest locally on Mac and passes Mach5 hs-tier1,2,3,4,5,6


Cheers