[thrust] Use CCCL Runtime in CUDA generate/tabulate tests

Part of #2800.

Use CCCL Runtime APIs in the Thrust CUDA generate/tabulate test family.

Candidate files:

- `thrust/testing/cuda/generate.cu`
- `thrust/testing/cuda/tabulate.cu`

This is a good follow-up for stream, launch, buffer, and result-helper patterns. Keep the PR comprehensive within the touched files but limited to this semantic pair.