Fix uses of throw/rethrow in tests.

tests/language/execute_finally10_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.
 
 // Regression test for dart2js that used to not treat the finally
 // block as a successor of a catch block that throws.
 
 import "package:expect/expect.dart";
- 
+
 class A {
   var field;
   start() {}
   stop() { field = 42; }
 }
 
 class B {
   var totalCompileTime = new A();
   var runCompiler = new Object();
 
   run() {
     totalCompileTime.start();
     try {
       throw 'foo';
     } catch (exception) {
       // Use [runCompiler] twice to ensure it will have a local
       // variable.
       runCompiler.toString();
       runCompiler.toString();
-      throw;
+      rethrow;
     } finally {
       totalCompileTime.stop();
     }
   }
 }
 
 main() {
   var b = new B();
   try {
     b.run();
     throw 'Expected exception';
   } catch (exception) {
     // Expected exception.
   }
 
   Expect.equals(42, b.totalCompileTime.field);
 }