kunit: Add KUnit memory block assertions to the example_all_expect_macros_test

Augment the example_all_expect_macros_test with the KUNIT_EXPECT_MEMEQ
and KUNIT_EXPECT_MEMNEQ macros by creating a test with memory block
assertions.

Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: David Gow <davidgow@google.com>