Build cuda.core RDC test fixtures without Bash

[rwgk]

This changes the cuda.core RDC test fixture build from a Bash script to a small Python driver around nvcc.

Why this change:

• The tests still require nvcc, but they no longer require Bash. That avoids Windows-specific ambiguity between Git Bash, WSL Bash, path conversion behavior, and environment propagation.
• The fixture builder now calls nvcc directly from Python with subprocess, using the platform's normal PATH lookup.
• The pathfinder lookup is removed intentionally. For the environments we care about, requiring nvcc to be on PATH is straightforward, matches normal CUDA command-line expectations, and avoids passing a full nvcc path through another layer.
• If local fixture files are absent, tests now distinguish between nvcc being unavailable, the host compiler environment being unavailable, and other nvcc failures. Only the first two become skips; unexpected nvcc failures still fail the test.

Suggested review path:

1. Review cuda_core/tests/test_binaries/build_test_binaries.py first. It is the Python replacement for the deleted Bash script.
2. Review _build_saxpy_rdc() in cuda_core/tests/test_module.py next. That is where the local fallback behavior and skip/fail policy lives.
3. Review the small CI workflow change last; it now runs nvcc --version to aid troubleshooting and then the Python fixture builder.

[copy-pr-bot]

Auto-sync is disabled for draft pull requests in this repository. Workflows must be run manually.

Contributors can view more details about this message here.

[rwgk]

/ok to test

[lijinf2]

Thanks for clarifying. I’m okay with keeping the current approach: bare nvcc from PATH, narrow skip classification for known host compilers, and fail visibly for unknown nvcc failures and log message updates.

One minor suggestion: please consider adding a short code comment/doc note that this test intentionally assumes nvcc is on PATH and a working host compiler environment is configured.

[rwgk]

Thanks @lijinf2!

One minor suggestion: please consider adding a short code comment/doc note that this test intentionally assumes nvcc is on PATH and a working host compiler environment is configured.

Done: commit aea8bb5

[github-actions]

Doc Preview CI
Preview removed because the pull request was closed or merged.

[leofang]

Thanks guys!