This will prevent false positives from occurring if the test is run on
ZFS since ZFS doesn't support fflags throbbing like UFS.
PR: 221189
MFC after: 4 days
MFC with: r321949
- :f_flag fails on ZFS because UF_IMMUTABLE isn't supported [1].
- :v_flag fails on ZFS because the mode for foo is [always] updated
unnecessarily.
get_filesystem(..) (supporting function that was added to the test script)
is based on equivalent logic in usr.bin/extattr/tests/extattr_test.sh .
MFC after: 1 week
PR: 221189 [1], 221188 [2]
