tracing/kprobe: Remove cleanup code unrelated to selftest

This cleanup all kprobe events code is not related to the selftest
itself, and it can fail by the reason unrelated to this test.
If the test is successful, the generated events are cleaned up.
And if not, we cannot guarantee that the kprobe events will work
correctly. So, anyway, there is no need to clean it up.

Link: https://lore.kernel.org/all/171811265627.85078.16897867213512435822.stgit@devnote2/



Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>