This constructs other stores from repos.Store on the fly rather than
storing them on the store struct. This is just to increase confidence
that, when we start a transaction, the next time we use a store, it
holds a handle to that transaction. I was really struggling to convince
myself that it was okay that we would start a transaction on the
basestore, but then use the untransacted store that we hold a reference
to on the store struct. I wasn't able to construct any failures, but
this still feels safer.
Note that I'm not confident this fixes incident 99 since I couldn't
reproduce it locally, but it might. I'm probably not going to be the
one to un-revert it and try though
Test plan
Depending on existing tests here, but I think this should be a safe change based on what I've read of the code.
