In this bug, we clean up the current implementation of FontSizeAdjust.
Pull request: https://github.com/WebKit/WebKit/pull/18833
<rdar://problem/116683371>
Committed 269124@main (cfb200931b4c): <https://commits.webkit.org/269124@main> Reviewed commits have been landed. Closing PR #18833 and removing active labels.