2to3: Mark legitimate python3 uses of range by using xrange instead.

Some of these that were not in the numpy directory were missed the
first time. This makes the replacements complete. The 2to3 conversion
will replaces xrange by range, i.e., using range in this way is
legitimate in both python 2 and python 3. The remaining use of range is
then replaced with list(range(*)).

The idea is to get the other fixups done, then replace all xrange with
range to finish the job.