The blockdev module is being slowly deprecated and its functions moved to
to the disk module instead. There is a test for resize2fs in the blockdev_test
file in the 2015.8 branch (which matches the resize2fs function in the blockdev
module), but this function was moved to the disk file in 2016.3. The test was
never moved over.
I discovered this during a merge forward in #36344. This PR adds the
test from 2015.8 blockdev_test to the 2016.3 disk_test.py, and is adjusted
to work with the disk module accordingly.