Remove literal tag (raw is more performant)

This reverts commit c00a650492.

lib/liquid.rb

@@ -45,7 +45,6 @@ module Liquid
   PartialTemplateParser       = /#{TagStart}.*?#{TagEnd}|#{VariableStart}.*?#{VariableIncompleteEnd}/
   TemplateParser              = /(#{PartialTemplateParser}|#{AnyStartingTag})/
   VariableParser              = /\[[^\]]+\]|#{VariableSegment}+\??/
-  LiteralShorthand            = /^(?:\{\{\{\s?)(.*?)(?:\s*\}\}\})$/
 end
 
 require 'liquid/drop'