Calling strong-globalize is relatively expensive (about 300
microseconds for each call). When using per-app local registry in
unit-tests, each app creation requires about 500 calls of `g.t` just
for remoting metadata, i.e. about 150ms.
In this commit, we introduce `g.s` that caches the results from
strong-globalize to speed up creation of remoting metadata.
3b88753c8e