Add a test for these #defines

Additionally, moved string_find_replace sub as it screws up subsequent
formatting when placed inside another sub.
Signed-off-by: NJoe Perches <joe@perches.com>
Suggested-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>