[llvm] [DebugInfo][RemoveDIs] Prevent duplicate DPValues from being returned by findDbgIntrinsics (PR #82764)

[Jeremy Morse via llvm-commits]

jmorse wrote:

findDbgIntrinsics can be a hot path -- would you be able to pump this through the compile-time-tracker please?

I think an alternative adding the `AllowEmpty=true` flag to the relevant call to `replaceVariableLocationOp`, if we can be confident there's a legitimate reason for there to be a duplicate entry when replacing.

https://github.com/llvm/llvm-project/pull/82764