[clang] [llvm] [LLVM] Use @llvm.compiler.used/@llvm.used helpers in Clang and BitcodeWriter (PR #162660)

[Juan Manuel Martinez Caamaño via llvm-commits]

jmmartinez wrote:

I've updated the PR after https://github.com/llvm/llvm-project/pull/164432 was merged.

The PR now only moves around the helpers and updates BitcodeWriter/CodeGenModule to use them.

https://github.com/llvm/llvm-project/pull/162660