[turbofan] Clean up cached nodes in JSGraph.

test/cctest/compiler/test-control-reducer.cc

Index: test/cctest/compiler/test-control-reducer.cc
diff --git a/test/cctest/compiler/test-control-reducer.cc b/test/cctest/compiler/test-control-reducer.cc
index c2b225ab009703a87fca31a8e9b24f671424070f..fb877e323c92443ba0d289ffdd5782e14ea3a399 100644
--- a/test/cctest/compiler/test-control-reducer.cc
+++ b/test/cctest/compiler/test-control-reducer.cc
@@ -400,6 +400,24 @@ TEST(Trim_constants) {
 }
 
 
+TEST(Trim_EmptyFrameState1) {
+  ControlReducerTester T;
+
+  Node* node = T.jsgraph.EmptyFrameState();
+  T.Trim();
+
+  for (Node* input : node->inputs()) {
+    CHECK_NOT_NULL(input);
+  }
+}
+
+
+TEST(Trim_EmptyFrameState2) {
+  ControlReducerTester T;
+  CheckTrimConstant(&T, T.jsgraph.EmptyFrameState());
+}
+
+
 TEST(CReducePhi1) {
   ControlReducerTester R;