Don't assume that set_num_threads inside a jitted function will propogate outside of it
Don't assume that set_num_threads inside a jitted function will propogate outside of it

See https://github.com/numba/numba/pull/4615#issuecomment-564503993

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