Debug information in client logs

In Snapshot 16w04 the client logs show some debug informations. Since these logs are not in the same format of the other, I have a good faith belief that some test system.out.println were left in the code.

added speed 0.0, 0.0, 0.0
added speed 0.0, 0.0, 0.0
added speed 0.0, 0.0, 0.0
added speed 0.0, 0.0, 0.0
added speed 0.0, 0.0, 0.0
added speed 0.0, 0.0, 0.0
[18:39:11] [Client thread/INFO]: Warning: Clientside chunk ticking took 109 ms
added speed 0.0, -0.0784000015258789, 0.0
added speed 0.0, 0.0, 0.0
added speed 0.0, -0.0784000015258789, 0.0
added speed 0.0, 0.0, 0.0