SendAddonMessage with WHISPER distribution to other realms crashes the client

[Meorawr]

In Cataclysm Classic beta build 4.4.0.54339 any usage of the SendAddonMessage API to send a WHISPER message to a player on a different realm triggers an immediate client crash.

Test case

1. Create a character on the Classic Beta PvE realm and log in.
2. Run the following command, and receive an immediate client crash.

/run C_ChatInfo.RegisterAddonMessagePrefix("test") C_ChatInfo.SendAddonMessage("test", "test", "WHISPER", "Anyone-ClassicBetaPvP")

• If the realm name is wholly invalid ("Potato"), the crash also occurs.
• If the destination realm name is omitted, or matches the current realm name ("ClassicBetaPvE") then no crash occurs.

[Meorawr]

Fixed in 4.4.0.54427.