Implemented ConstantPointerNullVal in getConstantData().
Implemented ConstantPointerNullVal in getConstantData().

mpflanzer/Oclgrind,mpflanzer/Oclgrind,bitfusionio/Oclgrind,surround-io/oclgrind,bitfusionio/Oclgrind,surround-io/oclgrind,bitfusionio/Oclgrind,mpflanzer/Oclgrind,surround-io/oclgrind,surround-io/oclgrind,bitfusionio/Oclgrind,mpflanzer/Oclgrind