[vector] optimize rotate left/right

[Paul Sandoz]

Hi,

We can implement the rotate left/right by composing with shift left/right and or:
 
  http://cr.openjdk.java.net/~psandoz/panama/bit-rotate-optimize/webrev/ <http://cr.openjdk.java.net/~psandoz/panama/bit-rotate-optimize/webrev/>

(Tests are needed for shift and rotate)

I made the methods final to indicate that they are considered suitable optimized (thus the test reporting on method overriding can skip these methods).

Paul.