ftracetest: Add ftrace basic testcases

Add ftrace basic testcases. This just checks ftrace debugfs
interface works as it is designed.

Link: http://lkml.kernel.org/p/20140922234252.23415.62897.stgit@kbuild-f20.novalocal

Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>