selftests/ftrace: Add syntax error test for multiprobe

Add syntax error test cases for multiprobe appending
errors.

Link: http://lkml.kernel.org/r/156095694541.28024.11918630805148623119.stgit@devnote2

Signed-off-by: Masami Hiramatsu <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
2 files changed