Address part of #28866, prevent array operations from dropping 0d containers

[mbauman]

This is a simple workaround for the handful of elementwise operations that are defined on arrays without the need for explicit broadcast but use broadcasting (with an extra shape check) in their implementation. These were the only affected cases I could find.

This is restoring the intended behavior, and matches the behavior of Julia pre-0.7. It is a fairly impactful change, though, so even though I'd call it a bugfix we probably want to be conservative in our backporting.

[StefanKarpinski]

Seems reasonable. I think whatever you end up deciding here is good, @mbauman.

[mbauman]

Failures were real and stemmed from the fact that LinearAlgebra specialized broadcast for adjoint/transposed vectors but didn't hook into the broadcast machinery. I initially tried to start addressing the root cause and move the specializations to the equivalent copy(::Broadcasted{...}) methods, but that ended up with effective ambiguities between this behavior and SparseArray's PromoteToSparse style. It'd be good to address this in the future but I wanted to keep this change as minimal as possible. So see #32289 for that change.

[StefanKarpinski]

Look at all those green checks 😁

[mbauman]

I say we do this.