Remove implicit_setter_test.

tests/language/implicit_setter_test.dart

-// 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.
-
-import "package:expect/expect.dart";
-
-// Test of final fields generating implicit setters that throw.
-
-String x = "toplevel";  // Should never be read in this test.
-
-class B {
-  var x = 37;
-}
-
-class C extends B {
-  final x = 42;
-
-  // Local access should work the same as direct access.
-  get cx => x;
-  void set cx(value) {
-    x = value;              /// 02: static type warning
-    erase(this).x = value;  // but crash even if the direct setting is omitted.
-  }
-
-  // Super access should work.
-  get bx => super.x;
-  void set bx(value) { super.x = value; }
-
-  noSuchMethod(i) => "noSuchMethod";  // Should never be called in this test.
-}
-
-// Class with only final field has setter in implicit interface.
-class A {
-  final int x = 42;
-}
-
-// Should get warning because the implicit interface contains the setter,
-// and this non-abstract class doesn't.
-class AI
-    implements A   /// 01: static type warning
-{
-  int get x => 37;
-}
-
-// Erases static type information. Used to avoid *static* warnings when
-// using a setter for a final field.
-erase(x) => x;
-
-void main() {
-  Expect.equals(42, new C().x);
-  Expect.throws(() { erase(new C()).x = 10; });
-  Expect.equals(42, new C().cx);
-  Expect.throws(() { erase(new C()).cx = 10; });
-  Expect.equals(37, new C().bx);
-  Expect.equals(10, (erase(new C())..bx = 10).bx);
-
-  Expect.equals(42, new A().x);
-  Expect.throws(() { erase(new A()).x = 10; });
-  Expect.equals(37, new AI().x);
-  Expect.throws(() { erase(new AI()).x = 10; });
-
-  Expect.equals("toplevel", x);  // Should not have changed.
-}