[llvm] [TableGen] Remove incorrect flag checking on patterns (PR #176443)

[Alex MacLean via llvm-commits]

AlexMaclean wrote:

Based on the discussion, I'm leaning towards just removing these checks entirely unless some one has a suggestion for how the could be made actually rigorous. In their current state I think they do not make much sense and are more likely to flag valid patterns than real bugs. 

https://github.com/llvm/llvm-project/pull/176443