Changes to range standalone iterator after review
Changes to range standalone iterator after review

Made changes @ronawho suggested in his review.

* Changed name of a variable from 'v' to 'len' and another from 'len' to
  'mylen' to avoid conflicting with the new 'len'

* Made suggested changes to avoid densifying/undensifying indices in
  non-stridable ranges.

* Added a TODO suggesting looking into avoiding densifying/undensifying
  in stridable ranges.

* Did not change 0..#numChunks to 0..numChunks-1 as hopefully the
  anonymous range optimization will work on ranges built with the count
  operator in the near future.

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