Feature: Sim mode at runtime #6820

Job	Run time
1/4	13m 50s
2/4	12m 59s
3/4	12m 34s
4/4	11m 38s
py-3-latest	19m 59s
flaky	6m 0s
_remote_background_indep_poll	5m 7s
_remote_background_indep_tcp	7m 21s
macos 1/5	21m 59s
macos 2/5	22m 49s
codecov	7s
	2h 14m 23s

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