Previously, we recreated the Harfbuzz face for each script-run. With this patch, we keep the Harfbuzz face in the FontPlatformData (created as needed) and so they will persist for the duration of the FontPlatformData. Shouldn't affect any layout tests.
Created attachment 33128 [details] patch
Created attachment 33133 [details] patch
Created attachment 33134 [details] patch
Comment on attachment 33134 [details] patch Seems fine.