[Interpreter] No need to read/return a value in GeneratorClose.

An oversight in Friday's CL. Thx to neis@chromium.org for the tip!

BUG=v8:6351
TBR=rmcilroy@chromium.org

Review-Url: https://codereview.chromium.org/2893223002
Cr-Commit-Position: refs/heads/master@{#45444}

src/interpreter/interpreter-intrinsics-generator.cc

@@ -437,13 +437,10 @@ Node* IntrinsicsGenerator::GeneratorGetResumeMode(Node* args_reg,
 Node* IntrinsicsGenerator::GeneratorClose(Node* args_reg, Node* arg_count,
                                           Node* context) {
   Node* generator = __ LoadRegister(args_reg);
-  Node* const value =
-      __ LoadObjectField(generator, JSGeneratorObject::kResumeModeOffset);
   __ StoreObjectFieldNoWriteBarrier(
       generator, JSGeneratorObject::kContinuationOffset,
       __ SmiConstant(JSGeneratorObject::kGeneratorClosed));
-
-  return value;
+  return __ UndefinedConstant();
 }
 
 Node* IntrinsicsGenerator::AsyncGeneratorReject(Node* input, Node* arg_count,