Optimize more megamorphic dispatch sites

pkg/analyzer/lib/src/generated/error_verifier.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.src.generated.error_verifier;
 
 import 'dart:collection';
 import "dart:math" as math;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 3795 matching lines @@
             _errorReporter.reportErrorForNode(
                 StaticWarningCode
                     .INSTANCE_METHOD_NAME_COLLIDES_WITH_SUPERCLASS_STATIC,
                 errorNameTarget,
                 [executableElementName, fieldElt.enclosingElement.displayName]);
             return true;
           }
         }
         // Check methods.
         List<MethodElement> methodElements = superclassElement.methods;
-        for (MethodElement methodElement in methodElements) {
+        int length = methodElements.length;
+        for (int i = 0; i < length; i++) {
+          MethodElement methodElement = methodElements[i];
           // We need the same name.
           if (methodElement.name != executableElementName) {
             continue;
           }
           // Ignore if private in a different library - cannot collide.
           if (executableElementPrivate &&
               _currentLibrary != superclassLibrary) {
             continue;
           }
           // instance vs. static
@@ skipping 2444 matching lines @@
 class _InvocationCollector extends RecursiveAstVisitor {
   final List<String> superCalls = <String>[];
 
   @override
   visitMethodInvocation(MethodInvocation node) {
     if (node.target is SuperExpression) {
       superCalls.add(node.methodName.name);
     }
   }
 }