Remove code supporting incremental compilation in dart2js

pkg/compiler/lib/src/compile_time_constants.dart

Index: pkg/compiler/lib/src/compile_time_constants.dart
diff --git a/pkg/compiler/lib/src/compile_time_constants.dart b/pkg/compiler/lib/src/compile_time_constants.dart
index 82459f35510892723bc5fc52b7e57a535f2756b7..4a0fee9d1ae6f8fdd690283c54952d0364035bb0 100644
--- a/pkg/compiler/lib/src/compile_time_constants.dart
+++ b/pkg/compiler/lib/src/compile_time_constants.dart
@@ -353,16 +353,6 @@ abstract class ConstantCompilerBase implements ConstantCompiler {
       MetadataAnnotation metadata, Node node, TreeElements elements) {
     return compileNodeWithDefinitions(node, elements);
   }
-
-  void forgetElement(Element element) {
-    initialVariableValues.remove(element);
-    if (element is ScopeContainerElement) {
-      element.forEachLocalMember(initialVariableValues.remove);
-    }
-    if (element is FunctionElement && element.hasFunctionSignature) {
-      element.functionSignature.forEachParameter(this.forgetElement);
-    }
-  }
 }
 
 /// [ConstantCompiler] that uses the Dart semantics for the compile-time