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

[Daniel Chen via cfe-commits]

DanielCChen wrote:

@jurahul 
It seems this PR is missing a test file `libcxxabi/test/test_demangle.pass.cpp`. 
It has a line of
```
{"_ZN4llvm9Intrinsic14getDeclarationEPNS_6ModuleENS0_2IDEPPKNS_4TypeEj", "llvm::Intrinsic::getDeclaration(llvm::Module*, llvm::Intrinsic::ID, llvm::Type const**, unsigned int)"},
```

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