Ensure inline elements in an empty linebox as having zero BSize and no baseline.
Also add meta viewport tag to the setup of /FileAPI/url/url-in-tags.window.js
WPT - This test passes now, but without this change, the test's viewport gets
automatically zoomed out when run on Android; and that zoom factor can lead to
off-by-one test failures from pixel-rounding discrepancies.
Differential Revision: https://phabricator.services.mozilla.com/D229191
bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1931466
gecko-commit: e2242ed908c0f7637c2b9277a674d5d0e1bcd09f
gecko-reviewers: layout-reviewers, dholbert, jfkthame