ART: MIR, SSARepresentation, and BasicBlock Additional API

Adding the API calls to the MIR structure to help with higher level code.
Some code has been added to BasicBlock as well for the removal.
Some code has also been added to SSARepresentation.
A constructor has been added to DecodedInstruction.

Change-Id: Ie65948d53d83fd8250545c94c88b442a68d702c7
Signed-off-by: Jean Christophe Beyler <jean.christophe.beyler@intel.com>
Signed-off-by: Razvan A Lupusoru <razvan.a.lupusoru@intel.com>
Signed-off-by: Yixin Shou <yixin.shou@intel.com>
Signed-off-by: Chao-ying Fu <chao-ying.fu@intel.com>
Signed-off-by: Udayan Banerji <udayan.banerji@intel.com>