Update language tests to new optional parameter syntax and semantics.

tests/language/compile_time_constant_i_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.
 
 class A {
   final x;
   const A(this.x);
   const A.redirect(x) : this(x + 1);
   const A.optional([this.x = 5]);
 }
@@ skipping 23 matching lines @@
 const a2 = const A.redirect(10499);
 const a3 = const A.optional();
 const a1b = const A.redirect(498);
 const a3b = const A(5);
 
 const b1 = const B(99499, -99499);
 const b2 = const B.redirect(1234, 5678);
 const b3 = const B.redirect2(112233, 556677);
 const b4 = const B.redirect3(332211, 776655);
 const b5 = const B.optional(43526);
-const b6 = const B.optional2(y: 9753, x:8642);
+const b6 = const B.optional2(8642, 9753);
 const b3b = const B(112233 + 122 + 1, 556677 + 122);
 const b6b = const B(8642, 9753);
 
 const c1 = const C(121, 232, 343);
 const c2 = const C.redirect(12321, 23432, 34543);
 const c3 = const C.redirect2(32123, 43234, 54345);
 const c4 = const C.redirect3(313, 424, 535);
 const c5 = const C.optional(191, 181, 171);
 const c6 = const C.optional(-191);
 const c7 = const C.optional2();
@@ skipping 41 matching lines @@
   Expect.equals(null, c6.y);
   Expect.equals(null, c6.z);
   Expect.equals(null, c7.x);
   Expect.equals(null, c7.y);
   Expect.equals(null, c7.z);
   Expect.equals(null, c8.x);
   Expect.equals(null, c8.y);
   Expect.equals(9911, c8.z);
   Expect.identical(c3, c3b);
 }