Support printing with LayoutNG, so that we no longer have to print using the legacy engine. Apart from getting the modern and more bugfree LayoutNG experience, this also adds support for the 'avoid' value to the break-before / break-after properties, since that's part of the core LayoutNG block fragmentation implementation that has already shipped (everywhere but printing). This means that we finally use LayoutNG everywhere, and we can soon start removing the legacy engine.
Implement support for printing in LayoutNG. LayoutNG block fragmentation shipped earlier this year (2022), first with only block container support, and later on flex, grid and tables. Now it's time for printing. https://bugs.chromium.org/p/chromium/issues/detail?id=1121942