Fix segfault on jit-function dtor when code is still running and the env is still in use
Fix segfault on jit-function dtor when code is still running and the env is still in use

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