Fix Flaky Tests

[paul-marechal]

These tests are flaky and should be fixed to make CI more reliable and more informative:

À propos the discussion here, this issue should be used to track tests that fail for no clear reason.

• 'workbench.editor.closeOnFileDelete' should close the editor when set to 'true'
• run reference code lens - this one is currently skipped, but its flakiness reflects a real problem with the display of code lenses: they often take a long time to appear for no very clear reason, and even when the editor leaves space between lines to render them.
• Different parts of the suite in launch-preferences.spec.js occasionally fail or time out. E.g.

Lately some failures of comparison where undefined !== null

• Recent PR's have seen some issues with Should toggle explorer and basic menu tests. Many logs about view containers having been disposed.
• A few failures that break down at the step of loading Mocha with messages like this:

loading mocha...
Uncaught Exception:  Error: Evaluation failed: TypeError: Cannot read property 'logger' of undefined
   at eval (eval at waitForPredicatePageFunction (:2:21), <anonymous>:3:66)
   at eval (eval at waitForPredicatePageFunction (:2:21), <anonymous>:3:73)

#11069 should help.

• Playwright tests cannot be run on MacOS: playwright: tests fail on MacOS #10793 will fix that.

• delete and add again file for dirty failed for Align focused button outline to vscode #11192 here

[vince-fugnitto]

I believe we can close as tests have been pretty stable lately. We can open individual issues whenever we encounter future flakiness.