[llvm] [Debuginfo][TailCallElim] Fix #86262: drop the debug location of entry branch (PR #86269)

[Stephen Tozer via llvm-commits]

SLTozer wrote:

For requesting reviews, you should add the prospective reviewers to the "Reviewers" list in the PR; @ mentions are better for one-off questions where you need a specific person's reply, and won't add the issue to their "Review requested" list.

https://github.com/llvm/llvm-project/pull/86269