RFR 8235492 : Update Prototype HashMap using inline classes

[Roger Riggs]

Updates to a prototype HashMap implementation using inline-classes and 
open hashing
and corresponding jmh tests.  The jmh tests are structured to compare 
the current HashMap
with the new HashMap in the jmh valhalla/corelibs/mapprotos package.
The performance is not quite up to the current HashMap metrics
so more investigation is needed.

Webrev:
http://cr.openjdk.java.net/~rriggs/webrev-inline-hashmap-micros-8235492/webrev-inline-hashmap-micros-8235492/webrev/

Regards, Roger