RFR(M): 8193130: Bad graph when unrolled loop bounds conflicts with range checks

[Roland Westrelin]

Hi Vladimir,

> http://cr.openjdk.java.net/~roland/8193130/webrev.01/
>
> After going back and force and debugging code myself I came almost to the same ideas as in this fix.
> I agree with it now. And sorry that it took long time.

Cool! Thanks for the review, testing and sponsoring.

> I am not sure about backport into JDK 10 which will be short lived. Changes are too complex and I 
> think they should "baked" in current JDK first.

Not backporting is fine with me.

Roland.