crc32c has an unkeyed test vector but crc32 did not.  Add the crc32c one
(which uses an empty input) to crc32 too, and also add a new one to both
that uses a nonempty input.  These test vectors verify that crc32 and
crc32c implementations use the correct default initial state.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>