Fix crash bug when deoptimizing from an optimized sqrt operation.

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';
 
 class ArithmeticTest {
 
@@ skipping 401 matching lines @@
   }
 
   static int div(a, b) => a ~/ b;
 
   static void testSmiDivDeopt() {
     var a = -0x40000000;
     var b = -1;
     for (var i = 0; i < 10; i++) Expect.equals(0x40000000, div(a, b));
   }
 
+  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));
+    Expect.throws(() => mySqrt("abc"));
+  }
+
   static testMain() {
     for (int i = 0; i < 1500; i++) {
       runOne();
       testSmiDivDeopt();
+      testSqrtDeopt();
     }
   }
 }
 
 main() {
   ArithmeticTest.testMain();
 }