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

[Stephen Tozer via llvm-commits]

================
@@ -0,0 +1,57 @@
+; RUN: opt -S -passes=tailcallelim < %s | FileCheck %s
+
+define dso_local i32 @func(i32 noundef %a) !dbg !10 {
+; CHECK: entry
----------------
SLTozer wrote:

```suggestion
; CHECK: entry:
```

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