Support constructor declarations 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 50eafcd54642426a39fa58cc671cdc2650ba9bb5..b1c6ac32714d2d54d9fd4dde0b5deb71800a7081 100644
--- a/pkg/analyzer2dart/test/end2end_data.dart
+++ b/pkg/analyzer2dart/test/end2end_data.dart
@@ -817,4 +817,15 @@ main(a) {
 }
 '''),
   ]),
+
+  const Group('Constructors', const <TestSpec>[
+    const TestSpec('''
+class C {
+  C() {}
+}
+main() {
+  return new C();
+}
+'''),
+  ]),
 ];