trim_line2

# File lib/erb.rb, line 350
      def trim_line2(line)
        head = nil
        line.split(TrimSplitRegexp).each do |token|
          next if token.empty?
          head = token unless head
          if token == "%>\n"
            yield('%>')
            if  is_erb_stag?(head)
              yield(:cr)
            else
              yield("\n")
            end
            break
          end
          yield(token)
        end
      end