Fleshed out two common subexpression tests that verify subexpression variables won't be destroyed, and that work isn't duplicated inside the kernels.
Fleshed out two common subexpression tests that verify subexpression variables won't be destroyed, and that work isn't duplicated inside the kernels.

stuartarchibald/numba,numba/numba,pombredanne/numba,seibert/numba,gmarkall/numba,jriehl/numba,pitrou/numba,stuartarchibald/numba,gdementen/numba,stefanseefeld/numba,sklam/numba,numba/numba,stefanseefeld/numba,stuartarchibald/numba,gmarkall/numba,cpcloud/numba,gdementen/numba,sklam/numba,IntelLabs/numba,gdementen/numba,jriehl/numba,cpcloud/numba,cpcloud/numba,sklam/numba,ssarangi/numba,gdementen/numba,IntelLabs/numba,sklam/numba,IntelLabs/numba,GaZ3ll3/numba,pitrou/numba,pombredanne/numba,seibert/numba,stuartarchibald/numba,ssarangi/numba,sklam/numba,stefanseefeld/numba,pitrou/numba,numba/numba,gmarkall/numba,GaZ3ll3/numba,IntelLabs/numba,stuartarchibald/numba,jriehl/numba,jriehl/numba,gmarkall/numba,numba/numba,pombredanne/numba,pitrou/numba,ssarangi/numba,pombredanne/numba,ssarangi/numba,gdementen/numba,gmarkall/numba,ssarangi/numba,cpcloud/numba,GaZ3ll3/numba,IntelLabs/numba,numba/numba,seibert/numba,stonebig/numba,GaZ3ll3/numba,jriehl/numba,stefanseefeld/numba,cpcloud/numba,stonebig/numba,stonebig/numba,stonebig/numba,seibert/numba,GaZ3ll3/numba,stefanseefeld/numba,pombredanne/numba,stonebig/numba,pitrou/numba,seibert/numba