80x regression in multidimensional `sort`

```julia
julia> @time sort(rand(100,100,50); dims=3); # 1.8.2
  0.026790 seconds (21 allocations: 11.445 MiB)

julia> @time sort(rand(100,100,50); dims=3); # master
  2.097280 seconds (20.02 k allocations: 37.265 GiB, 96.40% gc time)
```