Remove koans illustrating self-exit

I don't really like these examples, because the process would exit
anyway when the function returns... Also having to sleep is not ideal.

test/koans/processes_koans_test.exs

@@ -11,11 +11,9 @@ defmodule ProcessesTests do
       "hola!",
       :how_are_you?,
       {:waited_too_long, "I am impatient"},
-      false,
       {:multiple, [true, false]},
       {:exited, :random_reason},
       true,
-      false,
       :normal,
       :normal,
     ]