[CIR] Fix lowering after 2929a29

- After 2929a29,
  `ConversionPatternRewriter::replaceAllUsesWith` behavior is changed
  from the previous immediate mode into a delayed fashion. The legacy
  operation of `replaceAllUsesWith` followed by `eraseOp` is no longer
  working, replace that sequence with `replaceOp`.

Author: darkbuck

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -1355,8 +1355,7 @@ mlir::LogicalResult CIRToLLVMConstantOpLowering::matchAndRewrite(
     } else {
       const mlir::Value initVal =
           lowerCirAttrAsValue(op, op.getValue(), rewriter, typeConverter);
-      rewriter.replaceAllUsesWith(op, initVal);
-      rewriter.eraseOp(op);
+      rewriter.replaceOp(op, initVal);
       return mlir::success();
     }
   } else if (const auto recordAttr =
@@ -2653,8 +2652,7 @@ mlir::LogicalResult CIRToLLVMVTableGetVPtrOpLowering::matchAndRewrite(
   // pointer to the vptr type. Since the LLVM dialect uses opaque pointers
   // we can just replace uses of this operation with the original pointer.
   mlir::Value srcVal = adaptor.getSrc();
-  rewriter.replaceAllUsesWith(op, srcVal);
-  rewriter.eraseOp(op);
+  rewriter.replaceOp(op, srcVal);
   return mlir::success();
 }