ftrace/selftest: Test combination of function_graph tracer and function profiler

Masami reported a bug when running function graph tracing then the
function profiler. The following commands would cause a kernel crash:

  # cd /sys/kernel/tracing/
  # echo function_graph > current_tracer
  # echo 1 > function_profile_enabled

In that order. Create a test to test this two to make sure this does not
come back as a regression.

Link: https://lore.kernel.org/172398528350.293426.8347220120333730248.stgit@devnote2

Link: https://lore.kernel.org/all/20241010165235.35122877@gandalf.local.home/


Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>