tracing/kprobes: Add selftest scripts testing kprobe-tracer as startup test

Add two selftest scripts which tests kprobe-tracer as the startup
selftest does.
These test cases are testing that the kprobe_event can accept a
kprobe event with $stack related arguments and a kretprobe event
with $retval argument.

Link: http://lkml.kernel.org/p/20141008040307.13415.45145.stgit@kbuild-f20.novalocal
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>