dart2js: Destroy some type inference graph edges after type inference.

pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart

Index: pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
diff --git a/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart b/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
index 68cf701ff1467f387c9d2e877a8f1272abe7026a..418bd2d23728c6eecf5e6c962f299c5350a4f014 100644
--- a/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
+++ b/pkg/compiler/lib/src/inferrer/type_graph_inferrer.dart
@@ -1287,14 +1287,28 @@ class TypeGraphInferrerEngine
   }
 
   void clear() {
+    void cleanup(TypeInformation info) => info.cleanup();
+
+    allocatedCalls.forEach(cleanup);
     allocatedCalls.clear();
+
     defaultTypeOfParameter.clear();
-    types.typeInformations.values.forEach((info) => info.clear());
+
+    types.typeInformations.values.forEach(cleanup);
+
+    types.allocatedTypes.forEach(cleanup);
     types.allocatedTypes.clear();
+
     types.concreteTypes.clear();
+
+    types.allocatedClosures.forEach(cleanup);
     types.allocatedClosures.clear();
+
     analyzedElements.clear();
     generativeConstructorsExposingThis.clear();
+   
+    types.allocatedMaps.values.forEach(cleanup);
+    types.allocatedLists.values.forEach(cleanup);
   }
 
   Iterable<Element> getCallersOf(Element element) {