(Bug 62834) Accept multi-line comments in inline_breaks check

* Added a new parser test.

* But, it fails wt2html because of additional php attributes that
  our normalizer doesn't seem to be able to strip off. We have
  a lot of wt2html failures for headings. Either we fix our
  normalizer or add parsoid-specific html for these tests.
  This should be investigated separately.

Change-Id: Ie920e5c2ce307c223232c0fd2b82c880dd9a8eae
Merge "(Bug 62834) Accept multi-line comments in inline_breaks check"