[llvm] [JumpThreading][GVN] Copy metadata when inserting preload into preds (PR #134403)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Compile-time impact is high: https://llvm-compile-time-tracker.com/compare.php?from=89b09c80ebc1a198bf2eab81b5fcb9ba71a0f066&to=544f796aaf9c89e474928a3cca24c95647c09eb1&stat=instructions:u

https://github.com/llvm/llvm-project/pull/134403