[libshortfin] Build debug/asan

[marbre]

This adds a GitHub action to build a debug/asan version of libshortfin. Shallow cloning of dependencies obtained via FetchContent is reverted as the dependencies cannot be fetched in the CI.

Depends on #148

[stellaraccident]

Thanks. Left a number of comments but if it passes like this fine to land and iterate.

[stellaraccident]

You should add this to requirements.txt and pin it (to 2.0). This can/has broken before and will poison the cache.

(should also add the requirements.txt and requirements-tests.txt hashes to the pyenv hash if installing these packages as part of the pyenv build)

[marbre]

I added the the dependency to the requirements-tests.txt and pinned the version to 2.0.0. As it also specified as a build-system dep with line
https://github.com/nod-ai/sharktank/blob/b1d09dbf1496949929c9aaf11f3cd9c551975958/libshortfin/pyproject.toml#L6
nanobind version 2.1.0 is installed when executing pip install -v -e. later. Should this be pinned to 2.0.0 as well?

Based on the work you've reviewed so far, I further improved caching. Instead of adding hashes for the requirements.txt files to the pyenv/python build step, I added an additional cache on top to cache the dependencies. Assuming that the dependencies are changing more rapidly, this will reduce the build time of the cache. The step to install and cache the dependencies takes about 60s whereas building pyenv/python takes ~ 5m 45s.

[marbre]

Thanks for the review and the suggestions @stellaraccident. With commit 7e7b77e, the ASan build fails but it succeeds without the commit, see for example run https://github.com/marbre/sharktank/actions/runs/10560961944/job/29255953907.

As it is not passing for main, please re-approve if you want me to land it.