avoid "type DataType has no field size"

[visr]

This tries to avoid the issue described #147 that breaks this package on julia 1.9-DEV.

The julia change that triggers this is JuliaLang/julia#47170.
Looking at the changes in that PR I first tried to simply replace ty.size with Core.sizeof(ty), but that gave an error: "Type Symbol does not have a definite size."

Since

julia> isprimitivetype(Symbol)
false

julia> ismutabletype(Symbol)
true

I figured we could just use the short circuiting to avoid calling sizeof for Symbol by switching the order of the &&.

julia> (false || !true && error())
false

There may be a better way to fix this however.

[thautwarm]

Thanks for the PR. I'll also refine the solution.