[lld] [lld][ELF] Implement merged .debug_names section. (PR #86508)

[via llvm-commits]

cmtice wrote:

> How is the review of this going to proceed? Will there be a new PR, or changes ported to this PR?

The plan is for me to pull the changes Ray is making into this PR, and we'll go ahead with the review/commit with this PR.  I hope to have his changes migrated here by tomorrow.

https://github.com/llvm/llvm-project/pull/86508