tests: add move_mount(MOVE_MOUNT_SET_GROUP) selftest

Add a simple selftest for a move_mount(MOVE_MOUNT_SET_GROUP). This tests
that one can copy sharing from one mount from nested mntns with nested
userns owner to another mount from other nested mntns with other nested
userns owner while in their parent userns.

  TAP version 13
  1..1
  # Starting 1 tests from 2 test cases.
  #  RUN           move_mount_set_group.complex_sharing_copying ...
  #            OK  move_mount_set_group.complex_sharing_copying
  ok 1 move_mount_set_group.complex_sharing_copying
  # PASSED: 1 / 1 tests passed.
  # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0

Link: https://lore.kernel.org/r/[email protected]
Cc: Shuah Khan <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Mattias Nissler <[email protected]>
Cc: Aleksa Sarai <[email protected]>
Cc: Andrei Vagin <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: lkml <[email protected]>
Signed-off-by: Pavel Tikhomirov <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

0 files changed, 0 insertions, 0 deletions