[llvm] [DFAJumpThreading] Enable the pass by default (PR #83033)

[via llvm-commits]

XChy wrote:

The performance improvement brought by DFAJumpThreading looks fairly good to me. But it's uncertain whether we test this pass enough for correctness, especially with just few maintainance after the initial patch of DFAJumpThreading. To add it into the pipeline, I believe we need more correctness proofs apart from internal unit tests.

https://github.com/llvm/llvm-project/pull/83033