[Bug-apl] {rank operator}0

[Christian Robert]

      ⍴t
4 5
      t
 1 12 20 19  5
 6  2 14  3 16
17 11  7  9  4
15 10 18 13  8
      ⍴{2⍴⍵}⍤0 t
4 5 2
      ⍴{1⍴⍵}⍤0 t
4 5 1
      ⍴{0⍴⍵}⍤0 t
4 5 1
      ⍝ something wrong above, should be a 4x5x0 matrix
      ⍴{⍴⍵}⍤0 t
4 5 1
      ⍝ something wrong above, should be a 4x5x0 matrix