Integrate LLVM at 0d9b4394 (iree-org#18029)

Advance to llvm/llvm-project@0d9b4394

Existing local patches carried over:
* Still carrying a revert of
llvm/llvm-project@f6431f0c
* Still carrying a revert of
llvm/llvm-project@fa066687
* Still carrying a revert of
llvm/llvm-project@bbd4af5d

Signed-off-by: Benoit Jacob <jacob.benoit.1@gmail.com>