tests: add the f_badcluster test

This should have been part of commit 9a1d614df21 ("e2fsck: fix
rule-violating lblk->pblk mappings on bigalloc filesystems") but it
accidentally got dropped when the patch was applied.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>