Request for reviews (M): 7068051: SIGSEGV in PhaseIdealLoop::build_loop_late_post on T5440

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/7068051/webrev

Fixed  7068051: SIGSEGV in PhaseIdealLoop::build_loop_late_post on T5440

Changes I did for 7004535 are incorrect. They do not take into account that 
cloning/moving predicates below merge points invalidate jvm states recorded in 
predicate's uncommon trap. Removed predicate cloning from loop peeling 
optimization and from split fall-in paths. But left it in loop unswitching code 
which is safe, I think. Don't allow split loop entry path in IGVN optimization 
for Phi nodes. And do not clone predicates below merge points in split-if 
optimization. Removed move_loop_predicate() and eliminate_loop_predicates() 
unused methods.

Refworkload scores are not affected (sparc and x86).