/azp run STL-ASan-CI

If and when we merge this change, we need to update the Wiki page that describes how to recreate the pipelines: there's a manual UI step needed to require a maintainer comment before running a pipeline. Without that setting, STL-ASan-CI will now run automatically on all PRs.

As far as a can tell, there's no way to do this purely in YAML - which is why I didn't do so previously. I think the value of triggering the optional pipeline outweighs the annoyance of hand configuration. It's annoying to PR an ASan fix with no way to run the CI before merging.

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

Thanks for improving the ASAN experience! 📈 🎉 😸

If and when we merge this change, we need to update the Wiki page that describes how to recreate the pipelines: there's a manual UI step needed to require a maintainer comment before running a pipeline. Without that setting, STL-ASan-CI will now run automatically on all PRs.

I have updated the Wiki instructions.