selftests/ftrace: Add BTF arguments test cases

Add test cases to check the BTF arguments correctly supported.

Link: https://lore.kernel.org/all/168507478292.913472.25631899274942311.stgit@mhiramat.roam.corp.google.com/



Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>