[RemoveDIs][MLIR] Don't process debug records in the LLVM-IR translator (#89735)

We are almost ready to enable the use of debug records everywhere in
LLVM by default; part of the prep-work for this means ensuring that
every tool supports them. Every tool in the `llvm/` project supports
them, front-ends that use the `DIBuilder` will support them, and as far
as I can tell, the only other tool in the LLVM repo that needs to
support them but doesn't is `mlir-translate`. This patch trivially
unblocks them by converting from debug records to debug intrinsics
before translating a module.