[llvm] [TableGen] Rework error reporting for duplicate Feature/Processor. (PR #102257)

[Tomas Matheson via llvm-commits]

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

Thanks for working on this.

> * Change wording of error message when duplicate records are found to
>   be source code position agnostic, since `First` may not be before
>   `Second` lexically.

This seems like a (minor) regression in functionality, essentially reporting two random instances out of order. It would be nice if the order was preserved. Could you use line number as the tie breaker in the sort?

https://github.com/llvm/llvm-project/pull/102257