Align pattern vertex array with 4-byte boundary again

[mourner]

A follow-up to #12326, and an equivalent to the earlier #9681 (see there for the reasoning). Also might help with non-integer pixel ratios on data-driven pattern properties.

Launch Checklist

• briefly describe the changes in this PR
• write tests for all new functionality
• manually test the debug page
• apply changelog label ('bug', 'feature', 'docs', etc) or use the label 'skip changelog'

[mourner]

@SnailBones for some reason, I can't merge this PR because it says ci/circleci: test-render-linux-chrome-dev Expected — Waiting for status to be reported, even though the new browser test setup isn't yet even merged — do you know what might be going on?

[SnailBones]

@SnailBones for some reason, I can't merge this PR because it says ci/circleci: test-render-linux-chrome-dev Expected — Waiting for status to be reported, even though the new browser test setup isn't yet even merged — do you know what might be going on?

Yes, we changed the name of the test-render run to test-render-linux-chrome-dev to be more specific. It seems I was a bit hasty in updating the branch protection rules, I'll remove that requirement and re-add it after #12268 is merged.