`USE db/branch` works differently than `call dolt_checkout('branch')`

[zachmu]

There are subtle differences to how we manage session state between these two constructs. We need to unify them so they work identically.

[timsehn]

@fulghum did you fix this with your current work?

[timsehn]

I might close if we can't get more specific.

[fulghum]

No, I resolved some differences around database revision specs, but I think there are still more nuanced differences hiding in here.

[timsehn]

Closing this infavor of the more specific #5314