Update language tests to new optional parameter syntax and semantics.

tests/language/argument_definition_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.
 // Dart test program for testing argument definition test.
 
-int test(int a, [int b = 2, int c = 3]) {
+int test(int a, {int b: 2, int c: 3}) {
   int result = 0;
   ?b;
   ?result;  /// 01: compile-time error
   if (?a) {
     result += 100;
   }
   if (?b) {
     result += 20;
   }
   if (?c) {
     var b; ?b;  /// 02: compile-time error
     result += 3;
   }
   if ((!?a?!?b:!?c) == (?a??b:?c)) {
     result += 200;
   }
   if (!?a?!?b:!?c == ?a??b:?c) {
     result += 400;
   }
   return result;
 }
 
-closure_test(int a, [int b = 2, int c = 3]) {
+closure_test(int a, {int b: 2, int c: 3}) {
   var x = 0;
   return () {
     int result = 0;
     ?b;
     ?result;  /// 03: compile-time error
     ?x;  /// 04: compile-time error
     if (?a) {
       result += 100;
     }
     if (?b) {
@@ skipping 12 matching lines @@
       result += 400;
     }
     return result;
   };
 }
 
 main() {
   // Use a loop to test optimized version as well.
   for (int i = 0; i < 1000; i++) {
     Expect.equals(100, test(1));
-    Expect.equals(720, test(1, 2));
-    Expect.equals(523, test(1, 2, 3));
-    Expect.equals(703, test(1, c:3));
+    Expect.equals(720, test(1, b: 2));
+    Expect.equals(523, test(1, b: 2, c: 3));
+    Expect.equals(703, test(1, c: 3));
 
     Expect.equals(100, closure_test(1)());
-    Expect.equals(720, closure_test(1, 2)());
-    Expect.equals(523, closure_test(1, 2, 3)());
-    Expect.equals(703, closure_test(1, c:3)());
+    Expect.equals(720, closure_test(1, b: 2)());
+    Expect.equals(523, closure_test(1, b: 2, c: 3)());
+    Expect.equals(703, closure_test(1, c: 3)());
   }
 }