Projections do not play well with GPUCompiler

Here's an example that does not play well with GPUCompiler: https://gist.github.com/pabloferz/1390d85383e3243015be7ad5b162bcc4

A possible, but probably incomplete fix discussed with @mcabbott, is having the following specializations:

function ProjectTo(x::AbstractArray{T}) where {T <: AbstractFloat}
    return ProjectTo{AbstractArray}(; element=ProjectTo(zero(T)), axes=axes(x))
end

ProjectTo(x::AbstractArray{T}) where {T <: Bool} = ProjectTo{NoTangent}()

function (project::ProjectTo{AbstractArray})(dx::AbstractArray{S}) where {S <: Number}
    T = ChainRulesCore.project_type(project.element)
    return S <: T ? dx : map(project.element, dx)
end

Reproduce the GPUCompiler case from the linked gist, then inspect the existing ProjectTo behavior for AbstractArray values in ChainRulesCore. Compare the result with the proposed AbstractFloat, Bool, and Number specializations, and confirm the GPUCompiler example works without breaking projection behavior.