selftests: ftrace: Have some basic tests run in a tracing instance too

Some of the basic ftrace selftests should also be run in an instance. These
test a quick case of running all tracers in the available_tracers file
within the instance. The other is testing the clock used for the instance.
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

tools/testing/selftests/ftrace/test.d/00basic/basic2.tc

 #!/bin/sh
 # description: Basic test for tracers
+# flags: instance
 test -f available_tracers
 for t in `cat available_tracers`; do
   echo $t > current_tracer

tools/testing/selftests/ftrace/test.d/00basic/basic3.tc

 #!/bin/sh
 # description: Basic trace clock test
+# flags: instance
 test -f trace_clock
 for c in `cat trace_clock | tr  -d \[\]`; do
   echo $c > trace_clock