Revert two Kernel changes that were causing test failures.

tests/language_2/assignable_expression_test.dart

-// Copyright (c) 2013, 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 to detect syntactically illegal left-hand-side (assignable)
-// expressions.
-
-class C {
-  static dynamic field = 0;
-}
-
-dynamic variable = 0;
-
-main() {
-  variable = 0;
-  (variable) = 0; //   //# 01: compile-time error
-  (variable)++; //     //# 02: compile-time error
-  ++(variable); //     //# 03: compile-time error
-
-  C.field = 0;
-  (C.field) = 0; //  //# 11: compile-time error
-  (C.field)++; //    //# 12: compile-time error
-  ++(C.field); //    //# 13: compile-time error
-
-  variable = [1, 2, 3];
-  variable[0] = 0;
-  (variable)[0] = 0;
-  (variable[0]) = 0; //   //# 21: compile-time error
-  (variable[0])++; //     //# 22: compile-time error
-  ++(variable[0]); //     //# 23: compile-time error
-
-  C.field = [1, 2, 3];
-  (C.field[0]) = 0; //  //# 31: compile-time error
-  (C.field[0])++; //    //# 32: compile-time error
-  ++(C.field[0]); //    //# 33: compile-time error
-
-  var a = 0;
-  (a) = 0; //  //# 41: compile-time error
-  (a)++; //    //# 42: compile-time error
-  ++(a); //    //# 43: compile-time error
-
-  // Neat palindrome expression. x is assignable, ((x)) is not.
-  var funcnuf = (x) => ((x))=((x)) <= (x); // //# 50: compile-time error
-}