Incorrect /help behavior for non-ops

In previous versions, /help would only show the syntax for commands the user has access to. In the snapshots, typing /help on its own as a non-operator will list all commands.

Using /help <command> with the name of a valid command the user does not have access to, however, will yield java.util.NoSuchElementException. This is MC-121661.

It appears that non-operators have no knowledge of operator commands based on the above behavior and the fact that attempting to run any results in "unknown command" instead of the previous "you do not have permission to use this command."