Added templates to HTMLParserIdioms's isHTMLSpace and isNotHTMLSpace functions.

That is required as part of the review of CL https://codereview.chromium.org/23861003/
I also modified all the callers to those functions, to explicitly state the Character type.

BUG=284722

Review URL: https://chromiumcodereview.appspot.com/23792009

git-svn-id: svn://svn.chromium.org/blink/trunk@158123 bbb929c8-8fbe-4397-9dbb-9b2b20218538