RFR; 8240223: Use consistent predicate order in and with PhaseIdealLoop::find_predicate

[Stefan Karlsson]

Hi all,

Please review this patch to make the predicate search order consistent 
in PhaseIdealLoop::find_predicate and some of its usages.

https://cr.openjdk.java.net/~stefank/8240223/webrev.01/
https://bugs.openjdk.java.net/browse/JDK-8240223

The code wasn't broken before, but making the search order consistent, 
make it easier for the casual reader to more easily understand the code 
related to the loop predicates.

Minimal testing done, will run through tier1-3

Thanks,
StefanK