apply copy propagate fix var assignment handling
apply copy propagate fix var assignment handling

Copies should be killed if a variable is assigned,
e.g. constant or function call.

IntelLabs/numba,jriehl/numba,stuartarchibald/numba,cpcloud/numba,gmarkall/numba,stuartarchibald/numba,stuartarchibald/numba,IntelLabs/numba,gmarkall/numba,cpcloud/numba,numba/numba,numba/numba,jriehl/numba,stuartarchibald/numba,stonebig/numba,IntelLabs/numba,sklam/numba,numba/numba,gmarkall/numba,gmarkall/numba,sklam/numba,IntelLabs/numba,cpcloud/numba,seibert/numba,cpcloud/numba,numba/numba,cpcloud/numba,seibert/numba,stonebig/numba,numba/numba,jriehl/numba,sklam/numba,seibert/numba,sklam/numba,stonebig/numba,stonebig/numba,gmarkall/numba,stuartarchibald/numba,stonebig/numba,jriehl/numba,seibert/numba,jriehl/numba,seibert/numba,sklam/numba,IntelLabs/numba