util: Add a SHA1 unit test program

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
(cherry picked from commit 513d7ffa)
(cherry picked from commit 60ed1a07)

Squashed with:

util: scons: wire up the sha1 test

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Andres Gomez <agomez@igalia.com>
(cherry picked from commit 5d03a686)
(cherry picked from commit 455ff758)