tracing/selftests: Default to verbose mode when running in kselftest

In order to facilitate debugging of issues from automated runs of the ftrace
selftests turn on verbose logging by default when run from the kselftest
runner. This is primarily used by automated systems where developers may
not have direct access to the system so defaulting to providing diagnostic
information which might help debug problems seems like a good idea.

When tests pass no extra output is generated, when they fail a full log of
the test run is provided. Since this really is rather verbose when there are
a large number of test failures or output is slow (eg, with a serial
console) this could substantially increase the run time for the tests which
might present problems with timeout detection for affected systems,
hopefully we keep the tests running well enough that this is not too much
of an issue.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

tools/testing/selftests/ftrace/ftracetest-ktap

@@ -5,4 +5,4 @@
 #
 # Copyright (C) Arm Ltd., 2023
 
-./ftracetest -K
+./ftracetest -K -v