ART: Better SSA Allocation when recreating SSA

The SSA calculation is not allocation friendly. This makes the
SSARepresentation remember how much is allocated and not reallocate
if SSA should be recalculated.

Also added some allocation friendly code for the dominance code.

Change-Id: Icd5586b7e2fefae8e1535975ab400b1ca95b500f
Signed-off-by: Jean Christophe Beyler <jean.christophe.beyler@intel.com>
4 files changed