RFR(M): 8240248 : Extend superword reduction optimizations for x86

[Viswanathan, Sandhya]

Shravya and I would like to submit a webrev which extends super-word reduction optimizations to support and, or, xor reduction for x86.

JBS: https://bugs.openjdk.java.net/browse/JDK-8240248
Webrev: http://cr.openjdk.java.net/~sviswanathan/8240248/webrev.00/

Patch is extracted from vectorIntrinsics branch of Panama with additional changes to support auto-vectorization.

Please review,

Best Regards,
Sandhya