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

[Fangrui Song via llvm-commits]

MaskRay wrote:

I am sorry but I am going to revert this patch. The stage-2 IR verifier error is from a ThinLTO+SamplePGO build.

`-flto=thin -gsplit-dwarf -g -fdebug-info-for-profiling -fprofile-sample-use=` build of clang, a ThinLTO backend compile has
    assertion failures:

        Global is external, but doesn't have external or weak linkage!
        ptr @_ZN5clang12ast_matchers8internal18makeAllOfCompositeINS_8QualTypeEEENS1_15BindableMatcherIT_EEN4llvm8ArrayRefIPKNS1_7MatcherIS5_EEEE
        function declaration may only have a unique !dbg attachment
        ptr @_ZN5clang12ast_matchers8internal18makeAllOfCompositeINS_8QualTypeEEENS1_15BindableMatcherIT_EEN4llvm8ArrayRefIPKNS1_7MatcherIS5_EEEE

The failures somehow go away if -fprofile-sample-use= is removed.

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