minor refactor in merge_adjacent_blocks()
minor refactor in merge_adjacent_blocks()

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