Make the base sysimage not include any stdlibs

[KristofferC]

This is not needed since the sysimage we build on top of this will include all stdlibs that we need anyway.

Also, create a proper sysimage of the base sysimage (instead of a ji file) to improve precompilation performance of the parallel precompile we run using this sysimage.

This might as a side effect fix the CI errors on 1.10

[KristofferC]

I think with this implementation, this will fail to include e.g. LinearAlgebra when filter_stdlibs = false.

[JeffBezanson]

Fixes #783?

[KristofferC]

It should yes, let's split this PR into two so we can get that part in directly.