Bug 67657: Add normalized parameter names to templates

If the original parameter name had wikitext making it different
from the normalized name, a new attribute key.wt will contain the
original parameter name wikitext.

Add a new parameter to Util.tokensToString to also strip empty
line meta tokens.

New tests:
* Templates: Handle comments in parameter names (bug 67657).
  Blacklisted for html2wt as it's not possible to get the correct
  whitespace without data-parsoid, for now.
* Templates: Other wikitext in parameter names (bug 67657).
  Blacklisted for all cases but wt2wt, as the internal Parsoid
  template expander incorrectly reduces wikitext like ''1'' to a
  valid parameter name 1.

Change-Id: I466243013955df1990cdf93469bef8be9c80f96e
Merge "Bug 67657: Add normalized parameter names to templates"