[llvm] [llc] set canonical triple in module (PR #203725)

[Alex MacLean via llvm-commits]

AlexMaclean wrote:

> Can we add regression tests for the different divergence scenarios?

Done! It is somewhat tricky because there isn't a good way to match on the default triple but I think these at least confirm that something gets set in the module, which did not happen before. 

https://github.com/llvm/llvm-project/pull/203725