Add guard to parallel test on unsupported platforms
Add guard to parallel test on unsupported platforms

As title.

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