Optimize more megamorphic dispatch sites

pkg/analyzer/lib/src/dart/element/element.dart

Index: pkg/analyzer/lib/src/dart/element/element.dart
diff --git a/pkg/analyzer/lib/src/dart/element/element.dart b/pkg/analyzer/lib/src/dart/element/element.dart
index d46c864189b0b3cf1b6516337cd738da05af5e83..0ffc41ceb335f4960a1a82b391bad1a30a44e1a9 100644
--- a/pkg/analyzer/lib/src/dart/element/element.dart
+++ b/pkg/analyzer/lib/src/dart/element/element.dart
@@ -614,7 +614,9 @@ class ClassElementImpl extends ElementImpl
 
   @override
   PropertyAccessorElement getGetter(String getterName) {
-    for (PropertyAccessorElement accessor in _accessors) {
+    int length = _accessors.length;
+    for (int i = 0; i < length; i++) {
+      PropertyAccessorElement accessor = _accessors[i];
       if (accessor.isGetter && accessor.name == getterName) {
         return accessor;
       }
@@ -624,7 +626,9 @@ class ClassElementImpl extends ElementImpl
 
   @override
   MethodElement getMethod(String methodName) {
-    for (MethodElement method in _methods) {
+    int length = _methods.length;
+    for (int i = 0; i < length; i++) {
+      MethodElement method = _methods[i];
       if (method.name == methodName) {
         return method;
       }