[llvm] Fix error message when regalloc eviction advisor analysis could not be created (PR #72165)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

Yes, it is an atypical case. It very much depends on the type of error on whether or not the program exits. I'm not currently understanding your point about it being confusing if the error message assumes otherwise. The program does continue, doing exactly what is said in the error message. I'm also not sure what sort of "ignore all errors" flag would even be useful to suppress this message.

https://github.com/llvm/llvm-project/pull/72165