[Bug-apl] Trace doesn't display all lines

[Blake McBride]

Trace should show that it executed each line even if that line doesn't
produce a value.  i.e.

GNU APL:

      ∇test[⎕]∇
    ∇
[0]   test
[1]  ⍝ a comment
[2]   test2
[3]   x←4
    ∇
      ∇test2[⎕]∇
    ∇
[0]   test2
    ∇
      T∆test←⍳3
      test
test[3] 4



IBM APL 2:

      ∇TEST[⎕]∇
    ∇
[0]   TEST
[1]  ⍝ A COMMENT
[2]   TEST2
[3]   X←4
    ∇
      ∇TEST2[⎕]∇
    ∇
[0]   TEST2
    ∇
      T∆TEST←⍳3
      TEST
TEST[1]
TEST[2]
TEST[3] 4


Thanks.

Blake