[llvm] [github] Enable assertions on test workflow (PR #74849)

[Natalie Chouinard via llvm-commits]

sudonatalie wrote:

> > @tstellar A couple SPIR-V backend tests are XFAILed due to hitting assertions, so they're unexpectedly passing on the bot. We could change this for just SPIR-V tests but I'm presuming this is the preferred default for most others too?
> 
> I think the correct way to fix this is to add `REQUIRES: asserts` to the tests.

Ah, I'll make that change, thanks!

What do you think about enabling asserts anyways though? I would have expected that if a PR caused a passing test to hit an assert that it would cause that test to fail, and it looks like the [LLVM Buildbot Infrastructure docs](https://llvm.org/docs/HowToAddABuilder.html) generally suggest "Release build types with Assertions enabled".

https://github.com/llvm/llvm-project/pull/74849