RFR(S): 8146792: Predicate moved after partial peel may lead to broken graph

[Roland Westrelin]

http://cr.openjdk.java.net/~roland/8146792/webrev.00/

- partial peeling is applied to a loop 
- the peeled section is optimized and leaves a pinned node between the loop predicates and the loop body but no control flow 
- loop predicates are applied and a predicate that depends on the pinned node is moved out of the loop, before the pinned node, leading to a broken graph 

This is the same issue that came up during review of 8139771. Vladimir suggested it gets reviewed separately. With the included test case it reproduces without the change from 8139771.

Roland.