[llvm] [DA] remove constraint propagation (PR #160924)

[Ehsan Amiri via llvm-commits]

https://github.com/amehsan commented:

Just out of curisoty: Do we know this code is somehow buggier than other parts of DA and more difficult to fix, and not worth keeping under an option? I have read the comments and am aware of the reasons mentioned (and overall there seem to be agreement that removing is a good idea) but I was curious about this issue.

https://github.com/llvm/llvm-project/pull/160924