Request for reviews (L): 6340864: Implement vectorization optimizations in hotspot-server

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/6340864/webrev

6340864: Implement vectorization optimizations in hotspot-server

Added asm encoding and mach nodes for vector arithmetic instructions on x86.
Added new emit_*_arith() helper methods to simplify code for asm encoding.
Added few missing parts in superword code which already supports vector 
arithmetic (added code for vector MulI and URShiftI).

Note: these changes did not implement vectorization to get a sum of array's 
elements as bug's description asked - it needs more work.

Tested with compiler and java/lang regression tests, CTW and also provided 
vector arithmetic tests. I am converting those tests into compiler regression 
tests which will be included into these changes.

Thanks,
Vladimir