Based on the data collected by T254521, track and enforce wikitext limits for Parsoid to ensure it never (hardly ever) OOMs in production.

This task is to (say) set limits on input wikitext to X total bytes, Y lists, Z table cells, etc, and have Parsoid almost certain to complete processing in less than A CPU seconds and B MB heap size, and set those CPU and heap limits on the production cluster. Hopefully 99.<some number of nines>% of existing wikitext content falls under these limits; fixing the rest will be task Txxxx.