Request for reviews (S): 6662967: Optimize I2D conversion on new x86

[Vladimir Kozlov]

http://webrev.invokedynamic.info/kvn/6662967/index.html

Fixed 6662967: Optimize I2D conversion on new x86

Problem:
In new AMD cpu CVTDQ2PS and CVTDQ2PD are single direct path
instructions.

Solution:
Use CVTDQ2PS and CVTDQ2PD for integer values conversions
to float and double values on new AMD cpu.

Reviewed by:
Fix verified (y/n): y

Other testing:
JPRT