Support default constructors in analyzer2dart.

pkg/analyzer2dart/test/end2end_data.dart

Index: pkg/analyzer2dart/test/end2end_data.dart
diff --git a/pkg/analyzer2dart/test/end2end_data.dart b/pkg/analyzer2dart/test/end2end_data.dart
index 364dca525ea9de4593e7e412dc83a216321bdeb8..d43963859b6af640f4ef5f6c190627b34d0ee7f2 100644
--- a/pkg/analyzer2dart/test/end2end_data.dart
+++ b/pkg/analyzer2dart/test/end2end_data.dart
@@ -820,6 +820,13 @@ main(a) {
 
   const Group('Constructors', const <TestSpec>[
     const TestSpec('''
+class C {}
+main() {
+  return new C();
+}
+'''),
+
+    const TestSpec('''
 class C {
   C() {}
 }
@@ -827,6 +834,26 @@ main() {
   return new C();
 }
 '''),
+
+    const TestSpec('''
+class B {}
+class C extends B {
+  C() {}
+}
+main() {
+  return new C();
+}
+'''),
+
+    const TestSpec('''
+class B {
+  B() {}
+}
+class C extends B {}
+main() {
+  return new C();
+}
+'''),
   ]),
 
   const Group('Instance method', const <TestSpec>[