[llvm] [TableGen] Use vectors instead of sets for testing intersection. NFC. (PR #81602)

[Pierre van Houtryve via llvm-commits]

https://github.com/Pierre-vh approved this pull request.

If I understand correctly this doesn't change the logic of how the intersection is done, just the data structure used to hold the result of the intersection ? If so then LGTM

https://github.com/llvm/llvm-project/pull/81602