Eliminate old style import from language tests

tests/language/arithmetic_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 to test arithmetic operations.
 
-#library('arithmetic_test');
-#import('dart:math');
+library arithmetic_test;
+import 'dart:math';
 
 class ArithmeticTest {
 
   static bool exceptionCaughtParseInt(String s) {
     try {
       parseInt(s);
       return false;
     } on FormatException catch (e) {
       return true;
     }
@@ skipping 411 matching lines @@
     for (int i = 0; i < 1500; i++) {
       runOne();
       testSmiDivDeopt();
     }
   }
 }
 
 main() {
   ArithmeticTest.testMain();
 }