tracing: Add alternative synthetic event trace action test case

Add a test case for the alternative trace(<synthetic_event, params)
synthetic event generation syntax.

Link: http://lkml.kernel.org/r/0616d18423ab1dfdbf333bce9c92ac4fa0779207.1550100284.git.tom.zanussi@linux.intel.com



Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>