Move generated files to gen/.

test/codegen/cascade.dart

-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-class A {
-  var x;
-}
-
-void test_closure_with_mutate() {
-  var a = new A();
-  a.x = () {
-    print("hi");
-    a = null;
-  };
-  a
-    ..x()
-    ..x();
-  print(a);
-}
-
-void test_closure_without_mutate() {
-  var a = new A();
-  a.x = () {
-    print(a);
-  };
-  a
-    ..x()
-    ..x();
-  print(a);
-}
-
-void test_mutate_inside_cascade() {
-  var a;
-  a = new A()
-    ..x = (a = null)
-    ..x = (a = null);
-  print(a);
-}
-
-void test_mutate_outside_cascade() {
-  var a, b;
-  a = new A()
-    ..x = (b = null)
-    ..x = (b = null);
-  a = null;
-  print(a);
-}
-
-void test_VariableDeclaration_single() {
-  var a = []
-    ..length = 2
-    ..add(42);
-  print(a);
-}
-
-void test_VariableDeclaration_last() {
-  var a = 42,
-      b = []
-        ..length = 2
-        ..add(a);
-  print(b);
-}
-
-void test_VariableDeclaration_first() {
-  var a = []
-    ..length = 2
-    ..add(3),
-      b = 2;
-  print(a);
-}
-
-void test_increment() {
-  var a = new A();
-  var y = a
-    ..x += 1
-    ..x -= 1;
-}
-
-class Base<T> {
-  final List<T> x = <T>[];
-}
-
-class Foo extends Base<int> {
-  void test_final_field_generic(t) {
-    x..add(1)..add(2)..add(3)..add(4);
-  }
-}