[llvm] [LLVM][DWARF] Make some effort to avoid duplicates in .debug_ranges. (PR #106614)

[Kyle Huey via llvm-commits]

khuey wrote:

I've added a test.

I investigated one of the non-low-address duplicate cases and found that it originated in the LLVM components of rustc. Configuring the rustc build to use a clang that has this PR to compile its LLVM components eliminated all of the non-low-address duplicates, leaving only the duplicates created by --gc-sections.

https://github.com/llvm/llvm-project/pull/106614