Chrome processes remaining after concurrent headless tests finish (OSOE-839)

[Piedone]

Under Windows (didn't test other platforms), Chrome processes remain open after tests finish. Standard mode doesn't exhibit this issue.

See Lombiq/Open-Source-Orchard-Core-Extensions#738 (comment) and Lombiq/Open-Source-Orchard-Core-Extensions#738 (comment) for details. Contrary to what's written there though, this does happen in non-headless mode too, and also for single tests: Chrome processes (more than one for a test) are kept open, even though the Chrome Windows are closed.

This also happens with a single test being run: it'll leave 4 chrome.exe processes running, with 2 consuming some CPU (those relating to a test opening one Chrome for the Orchard Core setup, and another one for the test itself; no idea why there are two more processes).

This might just be fixed by #355.

Might be related: SeleniumHQ/selenium#13595.

Jira issue

[Piedone]

This might be behind #358.

@YevgeniyShunevych have you noticed Chrome processes not closing by chance?

[Piedone]

Hmm, removing no-sandbox fixes the issue in headless and non-headless too.

[Piedone]

@AydinE please watch this and merge from the OSOCE dev once this is closed.

[Piedone]

Or merge from the issue/OSOE-840 branch already.