Renames `populateVectorTransferCollapseInnerMostContiguousDimsPatterns`
as `populateDropInnerMostUnitDimsXferOpPatterns` + updates the
corresponding comments.
This addresses a TODO and makes the difference between these two
`populate*` methods clearer:
* `populateDropUnitDimWithShapeCastPatterns`,
* `populateDropInnerMostUnitDimsXferOpPatterns`.