Fix gpu dispatching on ReshapedArrays

[charleskawczynski]

This PR fixes gpu dispatching when the parent array fits into one of the following categories:

const cu_array = CUDA.CuArray
const TSubArray{T} = SubArray{<:Any, <:Any, <:T}
const TReshapedArray{T} = Base.ReshapedArray{<:Any, <:Any, <:T}

const CuArrayBackedTypes = Union{
    cu_array,
    TSubArray{cu_array},
    TSubArray{TReshapedArray{cu_array}},
    TSubArray{TReshapedArray{TSubArray{cu_array}}},
    TReshapedArray{cu_array},
    TReshapedArray{TSubArray{cu_array}},
}

After using launch_configuration for VIJFH datalayouts, this should fix #1854 (xref: #1854 (comment)).

This PR also changes to using CUDA's launch_configuration for the VF datalayouts, I'll take a look at the stencil benchmarks to see if/how the performance changes.

I've added a test only for DataLayouts fill!, as we use CuArrayBackedTypes for the copyto! kernels as well. We should probably add correctness tests for these other cases, as these composite arrays (and presumably their indexing) is, I imagine, quite complex.

The type declaration for CuArrayBackedTypes is rather complicated, and it seems impossible to define this for all possible types. I think we might need to switch to a dispatch solution, by recursing through the parent array until we either find Array or CuArray, and then dispatch on a 3rd argument.

[charleskawczynski]

Superseded by #1863