[AndrewJackson2020]

This PR adds the UBSAN sanitizer to the cassert build. It also adds and tests an example that will pass the non cassert build testing but will fail during the cassert build testing.

https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html

[steve-chavez]

Overall looks pretty good 👍

Only some errors on CI need to be cleared.

[AndrewJackson2020]

Overall looks pretty good 👍

Only some errors on CI need to be cleared.

Works on macos/clang, not sure why Linux/gcc is not working.

Edit. Seems like its just do to a different warning/error message. Interestingly gcc raises a runtime error with divide by zero while clang just moves past it.

[AndrewJackson2020]

I think this PR is in somewhat better shape. Took an embarrassingly long time to get it there, lots of issues along the way: long build/CI times (fixed mostly now), some non hermetic system leakages that prevent me from debugging locally that we still need to fix, one of the sanitizers straight up just doesn't work on macOS and causes hello world binaries to freeze at 100% CPU, etc.

That said I think this PR is mostly good at this point.