[llvm] [RemoveDIs] Load into new debug info format by default in LLVM (PR #89799)

[Stephen Tozer via llvm-commits]

SLTozer wrote:

Yep, I see that - MLIR currently doesn't support debug records; before translating IR to MLIR we convert to intrinsic-form, so there probably needs to be a conversion layer inserted that converts from intrinsic-form back to record-form in the reverse direction.

I'm also confused as to why the flto flag matters; iirc, the LLVM test suite configs with debug info are just `-O0 -g` or `-O3 -flto -g`, so it might just be that _any_ optimization with `-g` causes the error, and `-flto` is the only such config being run. Though it's also possible that the pipeline creates the IR module in a different way or at a different point that exposes the error.

https://github.com/llvm/llvm-project/pull/89799