test rename overhaul: step 8 - language tests

tests/language/src/AbstractSyntaxTest.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.
-
-main() {
-  var b = new B();
-  Expect.equals(42, b.foo());
-}
-
-class A {
-  abstract foo();
-  abstract static bar(); /// 01: compile-time error
-  static abstract baz(); /// 02: compile-time error
-}
-
-class B extends A {
-  foo() => 42;
-  bar() => 87;
-  baz() => 99;
-}