Tests: do not call vshard.storage.cfg before creating resources

[nurzhan-saktaganov]

In tests we call vshard.storage.cfg before creating methods, spaces and granting privileges.
It causes flaky tests, because sometimes vshard storage handles requests before fully initializing its resources.
We should initialize all resources and then call vshard.storage.cfg.
In the other hand, we can't call box.cfg{} manually - it should be called under the hood of vshard.storage.cfg.
No particular fix is suggested yet.

go-vshard-router/config.lua

Line 93 in 4995cc0

vshard.storage.cfg(cfg, names[NAME])