Deprecate Math object in corelib in favor of dart:math library.

tests/language/math_vm_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.
 // Tests that the VM does not crash on weird corner cases of class Math.
 // VMOptions=--optimization_counter_threshold=100
 
+#import('dart:math');
+
 class FakeNumber {
   const FakeNumber();
   void toDouble() {}
 }
 
 class MathTest {
   static bool testParseInt(x) {
     try {
-      Math.parseInt(x);  // Expects string.
+      parseInt(x);  // Expects string.
       return true;
     } catch (var e) {
       return false;
     }
   }
 
   static bool testSqrt(x) {
     try {
-      Math.sqrt(x);  // Expects number.
+      sqrt(x);  // Expects number.
       return true;
     } catch (var e) {
       return false;
     }
   }
 
   static void testMain() {
     Expect.equals(false, testParseInt(5));
     Expect.equals(false, testSqrt(const FakeNumber()));
   }
 }
 main() {
   for (int i = 0; i < 200; i++) {
     MathTest.testMain();
   }
 }