RFR: 8227505: SuperWordLoopUnrollAnalysis may lead to over loop unrolling

[Jie Fu]

Hi all,

JBS:    https://bugs.openjdk.java.net/browse/JDK-8227505
Webrev: http://cr.openjdk.java.net/~jiefu/8227505/webrev.00/

The patch fix the over loop unrolling problem caused by 
SuperWordLoopUnrollAnalysis.
For more info., please refer to the JBS.

Could you please review it and give me some advice?

Thanks a lot.
Best regards,
Jie