Migrated cascades tests from dart2js_extra into language tests

tests/compiler/dart2js_extra/cascade_test.dart

Index: tests/compiler/dart2js_extra/cascade_test.dart
diff --git a/tests/compiler/dart2js_extra/cascade_test.dart b/tests/compiler/dart2js_extra/cascade_test.dart
deleted file mode 100644
index e9f9b780ef3e68673578e8d78903f99dc8c60497..0000000000000000000000000000000000000000
--- a/tests/compiler/dart2js_extra/cascade_test.dart
+++ /dev/null
@@ -1,69 +0,0 @@
-// Copyright (c) 2012, 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.
-
-// Test cascades.
-
-class A {
-  int x;
-  int y;
-
-  A(this.x, this.y);
-
-  A setX(int x) { this.x = x; return this; }
-
-  void setY(int y) { this.y = y; }
-
-  Function swap() {
-    int tmp = x;
-    x = y;
-    y = tmp;
-    return this.swap;
-  }
-
-  void check(int x, int y) {
-    Expect.equals(x, this.x);
-    Expect.equals(y, this.y);
-  }
-
-  int operator[](var i) {
-    if (i == 0) return x;
-    if (i == 1) return y;
-    if (i == "swap") return this.swap;
-    return null;
-  }
-
-  int operator[]=(int i, int value) {
-    if (i == 0) {
-      x = value;
-    } else if (i == 1) {
-      y = value;
-    }
-  }
-
-  /**
-   * A pseudo-keyword.
-   */
-  import() {
-    x++;
-  }
-}
-
-main() {
-  A a = new A(1, 2);
-  a..check(1, 2)
-   ..swap()..check(2, 1)
-   ..x = 4..y = 9..check(4, 9)
-   ..setX(10)..check(10, 9)
-   ..y = 5..check(10, 5)
-   ..swap()()()..check(5, 10)
-   ..[0] = 2..check(2, 10)
-   ..setX(10).setY(3)..check(10, 3)
-   ..setX(7)["swap"]()..check(3, 7)
-   ..import()..check(4, 7)
-   ..["swap"]()()()..check(7, 4);
-  a.check(7,4);
-  a..(42);  /// 01: compile-time error
-  a..37;  /// 02: compile-time error
-  a.."foo";  /// 03: compile-time error
-}