Avoid ReshapedArray error when contiguous_axis is nothing and fix dense_dims

[Tokazama]

This is intended to fix #304. There were two examples where we had errors in that PR.

This is what I get with this PR.

julia> n = 4;

julia> u_plain = randn(1, n, n, 1);

julia> u_vectors = reshape(reinterpret(Tuple{eltype(u_plain)}, u_plain), n, n, 1);

julia> u_view = view(u_vectors, :, 1, 1);

julia> u_final = reshape(reinterpret(eltype(u_plain), u_view), 1, length(u_view));

julia> ArrayInterface.StrideIndex(u_final)
ArrayInterface.StrideIndex{2, (1, 2), 1, Tuple{Static.StaticInt{1}, Int64}, Tuple{Static.StaticInt{1}, Static.StaticInt{1}}}((static(1), 1), (static(1), static(1)))

and...

julia> ArrayInterface.contiguous_axis(Base.ReshapedArray{Float64, 2,
    Base.ReinterpretArray{Float64, 1,
         StaticArrays.SVector{1, Float64},
            SubArray{StaticArrays.SVector{1, Float64}, 1,
                Base.ReshapedArray{StaticArrays.SVector{1, Float64}, 3,
                    Base.ReinterpretArray{
                        StaticArrays.SVector{1, Float64}, 4, Float64,
                        Array{Float64, 4}, false},
                         Tuple{}},
                 Tuple{Base.Slice{Base.OneTo{Int64}}, Int64, Int64}, true}, false}, Tuple{}}})
static(1)

This also changes dense_dims(::ReshapedArray) to return all falses when we know that the parent array isn't dense.

[codecov]

Codecov Report

Merging #307 (d7a022e) into master (4245ffe) will increase coverage by 0.19%.
The diff coverage is 88.88%.

@@            Coverage Diff             @@
##           master     #307      +/-   ##
==========================================
+ Coverage   90.93%   91.13%   +0.19%     
==========================================
  Files           9        9              
  Lines        1401     1398       -3     
==========================================
  Hits         1274     1274              
+ Misses        127      124       -3     

Impacted Files	Coverage Δ
src/stridelayout.jl	89.80% <88.88%> (+0.64%)	⬆️

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