Fix issue 16103 (VM crash): incorrect merging of sin/cos.

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.
 // VMOptions=--optimization-counter-threshold=10 --no-use-osr
 
 library arithmetic_test;
 import "package:expect/expect.dart";
 import 'dart:math';
 
@@ skipping 417 matching lines @@
   static int divMod(a, b) => a ~/ b + a % b;
   
   static void testSmiDivModDeopt() {
     var a = -0x40000000;
     var b = -1;
     for (var i = 0; i < 10; i++) Expect.equals(0x40000000, divMod(a, b));
   }
   
   static double sinCosSub(double a) => sin(a) - cos(a);
   
+  static double sinCosAddCos(double a)  => sin(a) * cos(a) + cos(a);
+
   static void testSinCos() {
     var e = sin(1.234) - cos(1.234);
+    var f = sin(1.234) * cos(1.234) + cos(1.234);
+    
     for (var i = 0; i < 20; i++) {
       Expect.approxEquals(e, sinCosSub(1.234));
+      Expect.approxEquals(f, sinCosAddCos(1.234));
     }
     Expect.approxEquals(1.0, sinCosSub(3.14159265));
     Expect.approxEquals(1.0, sinCosSub(3.14159265 / 2.0));
   }
 
   static mySqrt(var x) => sqrt(x);
 
   static testSqrtDeopt() {
     for (var i = 0; i < 10; i++) mySqrt(4.0);
     Expect.equals(2.0, mySqrt(4.0));
@@ skipping 20 matching lines @@
       testSqrtDeopt();
       testDoubleEquality();
       testSinCos();
     }
   }
 }
 
 main() {
   ArithmeticTest.testMain();
 }