ftracetest: Add a couple of ftrace test cases

ftracetest: Add a couple of ftrace test cases

Added three test cases to get the feel of adding tests to ftracetest.
The three cases are:

  function profiling test, to make sure function profiling still works
   with function tracing (was a regression)

  function graph filter test to make sure that function graph filtering works.

  function graph filter with stack tracing test to make sure that the function
   graph filter does filter and also continues to filter when another function tracer
   is running (like the stack tracer)

Link: http://lkml.kernel.org/r/20141103212737.696365174@goodmis.org
Link: http://lkml.kernel.org/r/20141104153028.602754370@goodmis.org
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>