Add a testcase ensuring that the tracing error_log correctly displays
hist trigger parsing errors.

Link: http://lkml.kernel.org/r/62ec58d9aca661cde46ba678e32a938427945e9e.1561743018.git.zanussi@kernel.orgReviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>