Use value-based check for CUDA overload tests
Use value-based check for CUDA overload tests

Using prints and capturing stdout to test overloads is both overly
complicated and difficult to debug (terminal-based debuggers and
debug prints don't work during the tests). The value-based check that
replaces it suffers neither of these issues, and it is at least as clear
what each test does (more so, in my opinion).

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