Treat backslash as a universal escape character: "\n" is a newline,
backslash escapes any non-alphanumeric character.
This affects some test cases that had "\," standing for backslash-comma.
With the new uniform treatment of backslashes, this needs to be "\\,".
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>