CUDA: Support passing tuples to ufuncs - #6878

This commit adds support for use cases like the following to CUDA ufuncs
created with `@vectorize`:

```
from numba import vectorize, float64
import math

@vectorize([float64(float64)],)
def cuda_cos(x):
    return math.cos(x)

print(cuda_cos((1.0, 2.0, 3.0)))
```

Passing tuples, namedtuples, tuples of arrays, and nesting of these is
supported - tests are added to cover some of these cases.

It seems that this already worked for gufuncs, so some tests are added
for the equivalent in gufuncs, but no functional change is made there.

Fixes numba#6563.