Sorting issue when `Order` is not a full permutation

[eNascimento178]

If the defined Order values at the test file does not contains all numbers the JSON file can be sorted incorrectly:

This code below recreates the error:

variable_length_quantity_test_01_ignore=: 0
test_variable_length_quantity_test_01  =: monad define
  Description@.1 ('zero')
  Order@.1 (1)

  NB. integers=. 16b0
  NB. expected=. 16b0
  assert 16b0 = encode 16b0
)

variable_length_quantity_test_02_ignore=: 1 NB. Change this value to 0 to run this test
test_variable_length_quantity_test_02  =: monad define
  Description@.1 ('arbitrary single byte')
  Order@.1 (3) NB. skip the number two

  NB. integers=. 16b40
  NB. expected=. 16b40
  assert 16b40 = encode 16b40
)

Will look at this next week!