[lib/web/native] implement asserting store after processing ops for both web and native
Summary:
This is a pattern we used in the past, but now I want to make it work on all platforms.
Depends on D9759
Test Plan:
Call assertUserStoresAreEqual and check the result:
web:
native:
Reviewers: atul, tomek
Reviewed By: tomek
Subscribers: ashoat, wyilio
Differential Revision: https://phab.comm.dev/D9761