[llvm] [CI] Enable LTO linker plugin tests (PR #184076)

[Nikita Popov via llvm-commits]

nikic wrote:

Based on https://github.com/search?q=repo%3Allvm%2Fllvm-zorg%20LLVM_BINUTILS_INCDIR&type=code it looks like some sanitizer buildbots may be doing that.

https://github.com/llvm/llvm-project/pull/184076