You're going about this all wrong. GameConnection::spawnPlayer is called whenever a player spawns or respawns. You're(for some strange reason) trying to replace the entire function and turn it into a function that just loops a bottom print to the player.
What you should be doing is creating your own function to loop the bottom print and just use gameConnection::spawnPlayer to call the looping function.
You're also incorrectly creating a variable that you're doing nothing with and calling schedule wrong.
You should be handling the bottom print like this:
%filteredText = filterVariableString("\c6You got <var:cl:Test> Tests!", %client.processingBrick,%client,%client.player);
commandToClient(%client, 'bottomPrint', %filteredText, 0, 0);
And you should be doing the schedule something like this:
$MyFunction::Schedule = %client.schedule(250, MyFunction);