Request for reviews (XS): 6766316: assert(!nocreate,"Cannot build a phi for a block already parsed.")

[Vladimir Kozlov]

http://webrev.invokedynamic.info/kvn/6766316/index.html

Fixed 6766316: assert(!nocreate,"Cannot build a phi for a block already parsed.")

Problem:
The regression introduced by 6384206 fix.

Solution:
Don't use the invariant local information if there are irreducible loops.

Reviewed by:
Fix verified (y/n): y, failed test

Other testing:
JPRT, CTW