selftests: ftrace: Add more verbosity for immediate log

Add 3-level verbosity for showing traced command log
on console immediately. Since some test cases can cause
kernel pacic if there is a probrem (like regression etc.),
we can not know which command caused the problem without
traced command log. This verbosity (-vvv) solves that
because it shows the log on console immediately. User
can get continuous command/error log.

Note that this is a kind of kernel debug mode, if you
don't see any kernel related issue, you don't need this
verbosity.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <srostedt@goodmis.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>