move InteractiveUtils to stdlib

[JeffBezanson]

I kept dump and which for now.

Also deprecated which(::Symbol), since we have generally been removing functions that default to looking in Main.

Moved a few things to more logical places. _check_bitarray_consistency is now in Test. All the code for cpu_info is in Sys. Not sure what to do with Base.runtests; kept it for now. download obviously has non-interactive uses, so it stays. clipboard could go either way.

Closes #25751

[stevengj]

Wouldn't it be better to load these if the -i flag is set? Then it will automatically work in IJulia and other things that use julia -i.

[KristofferC]

This should remove the last usage of Pkg in Base.

[maleadt]

Is _dump_function really considered an interactive utility? It's also the main entry-point into the compiler as used by CUDAnative and the likes. Maybe we need a better API that can be part of Base then?

[JeffBezanson]

Ok, if you just need _dump_function, that can be moved back. But I agree there could be a better API --- is there some way it could be done without printing and re-parsing?

[fredrikekre]

This now gives:

WARNING: Base.versioninfo is deprecated: it has been moved to the standard library package `InteractiveUtils`.
Add a `using InteractiveUtils` to your imports..
 in module Base

when Base.runtests fail.
Edit: Not on only on failure, apparently always.

[maleadt]

Ok, if you just need _dump_function, that can be moved back. But I agree there could be a better API --- is there some way it could be done without printing and re-parsing?

Actually, there is already jl_get_llvmf_defn, I was only using _dump_function for 0.6 compatibility.
Let's use that directly; _dump_function and the likes can stay in InteractiveUtils then.