8226721: Missing intrinsics for Math.ceil, floor, rint

[Bhateja, Jatin]

Hi All,

Please find a patch with the following changes:- 
1) Intrincifiation for Math.ceil/floor/rint. 
2) Auto-vectorizer handling.

JBS: https://bugs.openjdk.java.net/browse/JDK-8226721
Webrev: http://cr.openjdk.java.net/~jbhateja/8226721/webrev.05 

Kindly review it.

Best Regards,
Jatin