RFR(S): 8215572: Add new Arrays micros

[Eric Caspole]

Hi everyone,

Could I have reviews on 2 new JMH micros for APIs Arrays.mismatch and 
Arrays.fill ,with no existing tests, which will be used for testing 
intrinsics and vectorization to Graal etc.

These will go into the test/micro that came with JEP 230.

Thanks,

Eric


JBS:

https://bugs.openjdk.java.net/browse/JDK-8215572

webrev:

http://cr.openjdk.java.net/~ecaspole/JDK-8215572/01/webrev/