tests: add the r_meta_bg_shrink test

This test checks to make sure resize2fs can properly handle a file
system which started life as a normal ext4 file system and then was
grown to a size where meta_bg was enabled, and then shrunk back below
the point where the meta_bg format is still needed.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
1 file changed