* Disable flaky test

Co-authored-by: clavin <clavin@electronjs.org>

* Add helper for storing test artifacts

Co-authored-by: clavin <clavin@electronjs.org>

* Refactor screen capture tests

We have a pattern for inspecting a screen capture, so this refactor codifies that pattern into a helper. This gives us shorter test code, consistency (previously, the display in test code and the display captured could theoretically be different), and better debugging/observability on failure.

Co-authored-by: clavin <clavin@electronjs.org>

---------

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: clavin <clavin@electronjs.org>