[clang] [llvm] [mlir] [polly] [NFC] Rename `Intrinsic::getDeclaration` to `getOrInsertDeclaration` (PR #111752)

[Daniel Chen via cfe-commits]

DanielCChen wrote:

We have downstream code that used `getDeclaration` and not we have changed to `getOrInsertDeclaration` for all places.
My understanding from reading the thread is that `getOrInsertDelcaration1 will stay and a new `findDeclaration` will be added temporarily and it will eventually become the new `getDeclaration` withe the new semantic. Do I miss anything there?


https://github.com/llvm/llvm-project/pull/111752