Include the CUDA call that failed in errors.

[tfogal]

To make debugging easier.

[kiskra-nvidia]

Thank you for your contribution!

While on some level more information never hurts, I'm not immediately convinced that this actually makes debugging easier?

WARN messages already include the source file and line number; mapping that info back to a CUDA should be a no-brainer. One could argue that INFO does not do that, but we don't seem to be using CUCHECKIGNORE anywhere in our current codebase.

So could you provide an example of when your PR makes a difference?

[tfogal]

We talked offline; this is slightly off the mark.

Follow-up on me to check behavior of GetLastError when the env var is not set and potentially rework this towards the goal of making GetLastError behave differently in that case. Draft mode until we're there.