Collect jq test suite digressions

[sshine]

This is a collection of digressions in the jq test suite.

They are collected here in a similar fashion to #4.

• jq segfaults when (0) is a key in a jq object:

  $ jq -n '{(0):1}'
  jq: jv.c:1110: jv_object_set: Assertion `jv_get_kind(key) == JV_KIND_STRING' failed.
  [1]    24306 abort (core dumped)  jq -n '{(0):1}'
  

  This appears to be a digression from the following case in tests/jq.test:

  %%FAIL
  {(0):1}
  jq: error: Cannot use number (0) as object key at <top-level>, line 1:
  

  Whereas input JSON with non-string keys in objects gives good errors:

  $ jq . <<< '{0:1}'
  parse error: Object keys must be strings at line 1, column 3