`COO @ COO`: fix to always produce coalesced outputs. (#91094)
Fixes [#90516](https://github.com/pytorch/pytorch/issues/90516)
Fixes [#90538](https://github.com/pytorch/pytorch/issues/90538)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/91094
Approved by: https://github.com/pearu
