RFR (S) : JDK-8245043 : Simplified contention benchmark

[eric.caspole at oracle.com]

Hi everyone,
Could you review this new JMH for lock contention and wait which started 
from trying to simplify what happens in Dacapo H2, but also I added more 
parameters to vary the size of time spent in locked and unlocked regions 
to cover more scenarios. Some combos of parameters here do track what we 
have observed in H2 in builds across 15. This should be easier to 
analyze going forward.

JBS:
https://bugs.openjdk.java.net/browse/JDK-8245043

Webrev:
http://cr.openjdk.java.net/~ecaspole/JDK-8245043/01/webrev/

Thanks,
Eric