Variable scope: don't lose metadata by passing around bare symbols

[pepijndevos]

I ran into another instance where the code takes a symbolic value, namespaces it, takes the name (discarding metadata) and uses that to rename the original symbol (with the old metadata).

This was not caught in the tests because the tests use renamespace directly and mostly used Sym rather than Term which trigger this code path. I've added a testcase for that now.

I seem to recall there was some test failure in a completely different test, so while I can't see why, I'm semi-expecting a CI failure. Let's see...

[pepijndevos]

Yeah that's the CI error I was expecting. Except I can't remember where it happened before and what I did to solve it. @YingboMa you remember by any chance?

I guess I need to figure out how to reproduce this testcase locally... bleg

[pepijndevos]

This failure does not seem to be cause by my changes. I checked out DataDrivenDiffEq.jl locally and it gives this test failure without my changes.

[ChrisRackauckas]

That's the symbolic array issues. Don't worry about DataDriven's failure.