A flaky test is found in this project and this PR proposes to fix it.

1. How to reproduce the flaky test

• The project is built and tested under javaJDK8.
• The tool used for the flaky test detection is NonDex.
• I ran mvn edu.illinois:nondex-maven-plugin:1.1.2:nondex -Dtest=fr.xephi.authme.listener.PlayerListenerTest#shouldHideChatFromUnauthed, which produces
  PlayerListenerTest.shouldHideChatFromUnauthed:348 Expected: iterable containing [<Mock for Player, hashCode: 775174220>, <Mock for Player, hashCode: 810672306>] but: item 0: was <Mock for Player, hashCode: 810672306>.

2. Why the test failed

• The method org.bukkit.event.player.AsyncPlayerChatEvent.getRecipients() called in the test fr.xephi.authme.listener.PlayerListenerTest.shouldHideChatFromUnauthed returns a set, which does not guarantee the order of the elements in it.

3. The changes made

• The contains in shouldHideChatFromUnauthed is changed to containsInAnyOrder, and the function org.hamcrest.Matchers.containsInAnyOrder is imported instead of org.hamcrest.Matchers.contains.