test: create a page in fixture tests to exercise browser processes (#3745)
test: create a page in fixture tests to exercise browser processes (#3745)

We currently launch and then close the empty browser. This does not
trigger many codepaths related to web page process creation and
browser context.

With opening and navigating a page, we do a more real-life test.
This exposes an issue from #3740.
microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright,microsoft/playwright