Simplify boolean condition compared to 0

CaffeineMarkRR Logic has some boolean flipping which can be helped by
some simplification.

Simplify non-FP (A COND_OP B) != 0 to A OPPOSITE_COND_OP B.
This is better than the original code, which would use a HBooleanNot
after the condition.

Also simplify non-FP (A COND_OP B) == 1 to A OPPOSITE_COND_OP B.

Move GetOppositeCondition to nodes.h/nodes.cc to share with Boolean
Simplification, renaming it to InsertOppositeCondition, as it inserts
the new HInstruction (unless it is a constant).

Change-Id: I34ded7758836e375de0d6fdba9239d2d451928d0
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>