(Bug 61770) Treat all block tags identically in pre-handler

* Pre-Handler had a check for HTML-syntax block tags (i.e. html
  tags that showed up in wikitext). But, xxtensions can generate
  block HTML content as well and need to suppress indent-pres
  as well.

* This patch removes the special case which fixes the bug.

* Added a new parser test but Parsoid's test runner doesn't have
  access to extensions and all those fail for that reason.

Change-Id: I2414ec53136f3012f749a601edea153333854349
Merge "(Bug 61770) Treat all block tags identically in pre-handler"