Use TokenStreamPatcher to convert table tags outside wikitables to text

* Keep track of table nesting in token stream patcher and use it to
  convert <td>, <tr>, and <th> tags to plain strings.

* This fix is only enabled on the top-level token stream.
  To support this, fixed the resetState function in the parser
  construction code to pass in a toplevel flag which lets the
  token stream patcher know the context it is in.

* Fixes 29 (wt2html,wt2wt,html2html,selser) tests and improves
  results of 1 previously blacklisted tests. The failing selser
  test is actually a false failure because selser is more accurate
  than non-selser wts.

* Consolidated a few separate tests into a single test that covers
  all this functionality.
  - This new test fails wt2wt and html2wt modes because serializer
    uses tokenizer information which continues to return table tokens
    and results in <nowiki> wrappers.

Bug: 66489
Bug: 66498
Change-Id: I9f42354ea9efb0f8adfc96c23760012220d00dd4
Merge "Use TokenStreamPatcher to convert table tags outside wikitables to text"