RFR 8177784 Use CounterMode intrinsic for AES/GCM

[Anthony Scarpino]

I'd like to get a review for this performance change to use the existing 
CounterMode parallelized intrinsic instead of GCTR's own version. The 
two classes were nearly identical except for the doFinal() method which 
doesn't belong in CounterMode.java.

I could have been more aggressive with this change, but I'm looking to 
get this into 9, so I stayed away from completely merging GCTR into 
CounterMode in case of incompatibilities.  All tests security and 
hotspot tests pass.

http://cr.openjdk.java.net/~ascarpino/8177784/webrev/

thanks

Tony