RFR:8243615 Continuous deoptimizations with Reason=unstable_if and Action=none

[Wang Zhuo(Zhuoren)]

Please review the following patch:
http://cr.openjdk.java.net/~wzhuo/8243615/webrev.01/
https://bugs.openjdk.java.net/browse/JDK-8243615

I met continuous deoptimization w/ Reason_unstable_if and Action_none in an online application and significant performance drop was observed.
It was found in JDK8 but I think it also existed in tip.

Regards,
Zhuoren