Replace most of 1-bit bitfields in RenderObjectBitfields with corresponding enum class flags like NodeFlags.
Pull request: https://github.com/WebKit/WebKit/pull/21996
Committed 272255@main (9b9eb59716b8): <https://commits.webkit.org/272255@main> Reviewed commits have been landed. Closing PR #21996 and removing active labels.
<rdar://problem/119853222>
Re-opening for pull request https://github.com/WebKit/WebKit/pull/22046
Committed 272282@main (31f3fa746c57): <https://commits.webkit.org/272282@main> Reviewed commits have been landed. Closing PR #22046 and removing active labels.