Migrate test block 1 to Dart 2.0.

tests/corelib/big_integer_huge_mul_vm_test.dart

-// Copyright (c) 2011, 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.
-
-// Testing Bigints with and without intrinsics.
-// VMOptions=
-// VMOptions=--no_intrinsify
-
-library big_integer_test;
-
-import "package:expect/expect.dart";
-
-testBigintHugeMul() {
-  var bits = 65536;
-  var a = 1 << bits;
-  var a1 = a - 1; // all 1's
-  var p1 = a1 * a1;
-  var p2 = a * a - a - a + 1;
-  // Use isTrue instead of equals to avoid trying to print such big numbers.
-  Expect.isTrue(p1 == p2, 'products do not match');
-}
-
-main() {
-  testBigintHugeMul();
-}