Test errors on 1.5 due to ambiguities caused by type piracy

[KristofferC]

This package and other dependencies fail on 1.5 due to ambiguities that this package introduces,

https://github.com/JuliaMatrices/ArrayLayouts.jl/blob/ba76345a24f0a6618fec80ab17193bfe7923543a/src/ArrayLayouts.jl#L83-L86

The test errors are of the form

  MethodError: unsafe_convert(::Type{Ptr{Float64}}, ::Adjoint{Float64,Array{Float64,2}}) is ambiguous. Candidates:
    unsafe_convert(::Type{Ptr{T}}, A::Adjoint{var"#s822",var"#s821"} where var"#s821"<:(StridedVecOrMat{T} where T) where var"#s822"<:Real) where T in LinearAlgebra at /opt/julia/share/julia/stdlib/v1.5/LinearAlgebra/src/adjtrans.jl:208
    unsafe_convert(::Type{Ptr{T}}, A::Adjoint{var"#s13",S} where S where var"#s13"<:Real) where T<:Real in ArrayLayouts at /home/pkgeval/.julia/packages/ArrayLayouts/S2dXf/src/ArrayLayouts.jl:83
  Possible fix, define
    unsafe_convert(::Type{Ptr{T}}, ::Adjoint{var"#s822",var"#s821"} where var"#s821"<:(StridedVecOrMat{T} where T) where var"#s822"<:Real) where T<:Real

It would be good to either remove these methods or try to get them into Base.

[dlfivefifty]

Right, these solved the same problem that a recent PR did JuliaLang/julia#29135

So I think we just add an if VERSION < v”1.5-dev” to only do these type piracy where needed.

[KristofferC]

If possible, it would be nice with a fix and a release since it would clean up the results a bit for the next 1.5 PkgEval run.

[dlfivefifty]

Those definitions seemed unnecessarily strict as they only overloaded for StridedArray so I made a PR: JuliaLang/julia#35929

If you can get that merged we can partially avoid type piracy. We will still need the ConjPtr overloads so perhaps they can be moved to Base, let's discuss in the other PR.