[DRAFT] Fix test flakes

[elliette]

No description provided.

[annagrin]

Btw I was running some tests on windows and saw those failures as well. The devtools_tests failures seem to be due to a race - we are waiting for couple of seconds after pressing Alt-D and before checking for existence of the devtools window, but it seems this is not always enough time. We might need a more reliable way of detecting when devtools window have started - one way could be by listening to dwds.events and waiting for DebuggerReady event .

webdev/dwds/test/devtools_test.dart

Line 39 in c1d2237

await Future.delayed(const Duration(seconds: 2));