removed new keyword (#75049)

packages/flutter_test/lib/src/finders.dart

@@ -58,8 +58,8 @@ class CommonFinders {
   ///
   /// ```dart
   /// // Suppose you have a button with text 'Update' in it:
-  /// new Button(
-  ///   child: new Text('Update')
+  /// Button(
+  ///   child: Text('Update')
   /// )
   ///
   /// // You can find and tap on it like this:
@@ -125,8 +125,8 @@ class CommonFinders {
   ///
   /// ```dart
   /// // Suppose you have a button with icon 'arrow_forward' in it:
-  /// new Button(
-  ///   child: new Icon(Icons.arrow_forward)
+  /// Button(
+  ///   child: Icon(Icons.arrow_forward)
   /// )
   ///
   /// // You can find and tap on it like this:
@@ -167,8 +167,8 @@ class CommonFinders {
   ///
   /// ```dart
   /// // Suppose you have a button created like this:
-  /// Widget myButton = new Button(
-  ///   child: new Text('Update')
+  /// Widget myButton = Button(
+  ///   child: Text('Update')
   /// );
   ///
   /// // You can find and tap on it like this:

packages/flutter_test/lib/src/test_compat.dart

@@ -144,11 +144,11 @@ Future<void> _runSkippedTest(Suite suiteConfig, Test test, List<Group> parents,
 ///       // ...
 ///     }, onPlatform: {
 ///       // This test is especially slow on Windows.
-///       'windows': new Timeout.factor(2),
+///       'windows': Timeout.factor(2),
 ///       'browser': [
-///         new Skip('TODO: add browser support'),
+///         Skip('TODO: add browser support'),
 ///         // This will be slow on browsers once it works on them.
-///         new Timeout.factor(2)
+///         Timeout.factor(2)
 ///       ]
 ///     });
 ///

packages/flutter_test/lib/src/widget_tester.dart

@@ -100,7 +100,7 @@ typedef WidgetTesterCallback = Future<void> Function(WidgetTester widgetTester);
 ///
 /// ```dart
 /// testWidgets('MyWidget', (WidgetTester tester) async {
-///   await tester.pumpWidget(new MyWidget());
+///   await tester.pumpWidget(MyWidget());
 ///   await tester.tap(find.text('Save'));
 ///   expect(find.text('Success'), findsOneWidget);
 /// });
@@ -371,8 +371,8 @@ const String kDebugWarning = '''
 ///     main() async {
 ///       assert(false); // fail in checked mode
 ///       await benchmarkWidgets((WidgetTester tester) async {
-///         await tester.pumpWidget(new MyWidget());
-///         final Stopwatch timer = new Stopwatch()..start();
+///         await tester.pumpWidget(MyWidget());
+///         final Stopwatch timer = Stopwatch()..start();
 ///         for (int index = 0; index < 10000; index += 1) {
 ///           await tester.tap(find.text('Tap me'));
 ///           await tester.pump();