Move the crypto tests into the pkg directory

tests/lib/crypto/hmac_sha256_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.
-
-// Library tag to allow the test to run on Dartium.
-library hmac_sha256_test;
-
-import "package:expect/expect.dart";
-import "package:crypto/crypto.dart";
-
-part 'hmac_sha256_test_vectors.dart';
-
-void testStandardVectors(inputs, keys, macs) {
-  for (var i = 0; i < inputs.length; i++) {
-    var hmac = new HMAC(new SHA256(), keys[i]);
-    hmac.add(inputs[i]);
-    var d = hmac.close();
-    Expect.isTrue(CryptoUtils.bytesToHex(d).startsWith(macs[i]), '$i');
-  }
-}
-
-void main() {
-  testStandardVectors(hmac_sha256_inputs, hmac_sha256_keys, hmac_sha256_macs);
-}