test: don't hard code deprecation count

PR-URL: https://github.com/nodejs/node/pull/7927
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Claudio Rodriguez <cjrodr@yahoo.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/parallel/test-crypto-deprecated.js

@@ -9,6 +9,11 @@ if (!common.hasCrypto) {
 const crypto = require('crypto');
 const tls = require('tls');
 
+const expected = [
+  'crypto.Credentials is deprecated. Use tls.SecureContext instead.',
+  'crypto.createCredentials is deprecated. Use tls.createSecureContext instead.'
+];
+
 process.on('warning', common.mustCall((warning) => {
   assert.strictEqual(warning.name, 'DeprecationWarning');
   assert.notStrictEqual(expected.indexOf(warning.message), -1,
@@ -16,12 +21,7 @@ process.on('warning', common.mustCall((warning) => {
   // Remove a warning message after it is seen so that we guarantee that we get
   // each message only once.
   expected.splice(expected.indexOf(warning.message), 1);
-}, 2));
-
-var expected = [
-  'crypto.Credentials is deprecated. Use tls.SecureContext instead.',
-  'crypto.createCredentials is deprecated. Use tls.createSecureContext instead.'
-];
+}, expected.length));
 
 // Accessing the deprecated function is enough to trigger the warning event.
 // It does not need to be called. So the assert serves the purpose of both