[clang] [CIR] Defer emitting function definitions (PR #142862)

[Bruno Cardoso Lopes via cfe-commits]

================
@@ -1523,6 +1523,50 @@ cir::FuncOp CIRGenModule::getOrCreateCIRFunction(
   cir::FuncOp funcOp = createCIRFunction(
       invalidLoc ? theModule->getLoc() : getLoc(funcDecl->getSourceRange()),
       mangledName, mlir::cast<cir::FuncType>(funcType), funcDecl);
+
+  if (!dontDefer) {
----------------
bcardosolopes wrote:

In order to diminish levels of indentation, should this return early otherwise?
```
if (dontDefer)
  return funcOp
// rest of code
```

https://github.com/llvm/llvm-project/pull/142862