refactor const index matching to use stencil IR
refactor const index matching to use stencil IR

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