Add a test to the tracing selftests that will catch if the .sym or
.sym-offset modifiers break in the future.

Link: https://lkml.kernel.org/r/20210707121451.101a1002@oasis.local.homeAcked-by: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>