Implements a BasicBlock iterator using the ArenaBitVector.

Added the implementation of a BasicBlock iterator using the ArenaBitVector.
This patch only adds the implementation of the iterator and does not yet use
 it everywhere it could be.

Added one example in ssa_transformation.cc of its use.

Change-Id: Ia85d58320c80c48a43609265ea5318a416c71f18
Signed-off-by: Jean Christophe Beyler <jean.christophe.beyler@intel.com>
3 files changed