Make test in @superset-ui/dimension use fake timers

[kristw]

Is your feature request related to a problem? Please describe.
Tests are using real timers. If this can be switch to fake timers, it can complete faster.

Describe the solution you'd like
Wait time due to real timer is greatly reduced.

Describe alternatives you've considered
Now the tests are using real timers and we accept 0.5s wait time for the action to happen before assertion.

Additional context
extracted from #281

[villebro]

The codebase on this repo has been moved to the main Apache Superset repo, and consequently the repo is in the process of being archived. See the Superset Improvement Proposal for details: apache/superset#13013 . While all currently open issues and PRs will be closed, we encourage you to reopen this issue on the main repo if it is still relevant.