Fix internal indices calculation for non-compute partitions (#691)
Fix internal indices calculation for non-compute partitions (#691)

* Fix internal indices calculation for non-compute partitions

* Resolves #690
* Previously we were always triggering computation on the first
  partition, but now we filter it out if there is nothing to compute.

* Address comment

Co-Authored-By: William Ma <d59a250e68833655a6b17f8074d623271b8cf748@users.noreply.github.com>

modin-project/modin,modin-project/modin