test: slre: add tests for character ranges

The first of these, { "U-Boot", "^[B-Uo-t]*$", 0 }, would match
previously when the - and the letters were all interpreted literally.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Rasmus Villemoes <ravi@prevas.dk>
1 file changed