(Bug 72487) More robust handling of <td> split across page & template

* The td-fixup code wasn't handling comments.

* Updated tests to test this scenario as well.
  - Also merged two tests into one since they were testing similar
    things and added additional scenarios.

* idwiki/Nickelodeon_Kids%27_Choice_Awards?oldid=8237629 now
  renders properly (except for one cell which has a broken comment).

Change-Id: I7da4fb88c47d10899b0698d24033921810b9834c