Revert "Move at::{Refcounted,}MapAllocator to c10 (#109881)"
This reverts commit 68a1219f74467a4d2124288f3ab6f8bc471fe4a1.
Reverted https://github.com/pytorch/pytorch/pull/109881 on behalf of https://github.com/kit1980 due to breaking internal builds, undefined symbol: _ZN3c1022RefcountedMapAllocator6decrefEv ([comment](https://github.com/pytorch/pytorch/pull/109881#issuecomment-1761950014))
