[llvm] [DebugInfo][RemoveDIs] Add a DPValue implementation for instcombine sinking (PR #77930)

[Jeremy Morse via llvm-commits]

jmorse wrote:

(Immediate observation; the compile-time difference observe on the O3 configuration is likely because we want an early-out when there's no debug-info, which I'll add).

https://github.com/llvm/llvm-project/pull/77930