Revert "Add all_reduce_coalesced functional collective (#97157)"
This reverts commit a3fc3531f514d4c01de9c4a60f978d704d615494.
Reverted https://github.com/pytorch/pytorch/pull/97157 on behalf of https://github.com/huydhn due to Sorry for reverting your PR, but it seems to have a land race with https://github.com/pytorch/pytorch/pull/96226 and fails lint on trunk
