feat(dart/transform): Use the best available Change Detectors

Enable pregenerated (for Dart) and JIT (for Js) change detectors when
possible. Previously we would always use `DynamicChangeDetector`s, but
these cause megamorphic calls and are therefore much slower.

Closes #502

modules/angular2/test/transform/directive_metadata_extractor/directive_metadata_files/changeDetection.ng_deps.dart

@@ -22,8 +22,6 @@ void initReflector(reflector) {
     ..registerType(HelloCmp, {
       'factory': () => new HelloCmp(),
       'parameters': const [const []],
-      'annotations': const [
-        const Component(changeDetection: 'CHECK_ONCE')
-      ]
+      'annotations': const [const Component(changeDetection: 'CHECK_ONCE')]
     });
 }

modules/angular2/test/transform/directive_metadata_extractor/directive_metadata_files/events.ng_deps.dart

@@ -22,8 +22,6 @@ void initReflector(reflector) {
     ..registerType(HelloCmp, {
       'factory': () => new HelloCmp(),
       'parameters': const [const []],
-      'annotations': const [
-        const Component(events: ['onFoo', 'onBar'])
-      ]
+      'annotations': const [const Component(events: ['onFoo', 'onBar'])]
     });
 }

modules/angular2/test/transform/integration/two_annotations_files/expected/bar.ng_deps.dart

@@ -20,6 +20,8 @@ void initReflector(reflector) {
         const View(template: 'Salad')
       ]
     });
+  _gen.preGeneratedProtoDetectors['MyComponent_comp_0'] =
+      _MyComponent_ChangeDetector0.newProtoChangeDetector;
 }
 class _MyComponent_ChangeDetector0 extends _gen.AbstractChangeDetector {
   final dynamic _dispatcher;