Rollup merge of rust-lang#146631 - Zalathar:di-builder, r=nnethercote

cg_llvm: Replace some DIBuilder wrappers with LLVM-C API bindings (part 3)

- Part of rust-lang#134001
- Follow-up to rust-lang#136375
- Follow-up to rust-lang#136632

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This is another batch of LLVMDIBuilder binding migrations, replacing some our own LLVMRust bindings with bindings to upstream LLVM-C APIs.

This PR migrates all of the bindings that were touched by rust-lang#136632, plus `LLVMDIBuilderCreateStructType`.

Author: Zalathar