desc: r.minval can't be confused with an empty array. This used to crash.
table_variable_name: tbl
tests:
    - py: tbl.index_create("v")
      ot: {"created": 1}
    - py: tbl.index_wait("v")
    - py: tbl.insert({"id": 1, "v": []})
      ot: partial({"inserted": 1})
    - py: tbl.between([r.minval], [r.maxval], left_bound="open", index="v").count()
      ot: 0