[llvm] [Analysis] Ensure use of strict fp exceptions in ConstantFolding (PR #136139)

[Simon Tatham via llvm-commits]

https://github.com/statham-arm commented:

I agree with the general idea, but I have a nit in the details.

(Also, today I learned you could use `set_source_files_properties` to change the build options for one file without creating a separate whole target, thank you!)

https://github.com/llvm/llvm-project/pull/136139