Remove test delays (#5579)

* Changing __indexBuildCompletionCallbackForTests callback to serverStartComplete

* Improving serverStartComplete callback to avoid production unhandled promise rejection

* Add test to check inexistence of unhandled promise rejection on server fail

* Removing some hooks delays

* Removing delay after reconfigureServer

* Improving code style

spec/support/FailingServer.js

@@ -0,0 +1,10 @@
+#!/usr/bin/env node
+
+const ParseServer = require('../../lib/index').ParseServer;
+
+ParseServer.start({
+  appId: 'test',
+  masterKey: 'test',
+  databaseURI:
+    'mongodb://doesnotexist:27017/parseServerMongoAdapterTestDatabase',
+});