Notes:
- This removes Parser::FunctionState and PreParser::FunctionState and adds
ParserBase::FunctionState etc.
- Also the scope stacks and function state stacks are moved to ParserBase.
- PreParser::FunctionState didn't add and subtract
JSFunction::kLiteralsPrefixSize (unlike Parser::FunctionState). Since the
actual value of NextMaterializedLiteralIndex is not used in the Preparser,
this change is valid.
- Traits no longer need functions like is_classic_mode(), since now there is a
 unified way of getting the information from the FunctionState / Scope.

R=ulan@chromium.org
BUG=v8:3126
LOG=N

Review URL: https://codereview.chromium.org/135213007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19361 ce2b1a6d-e550-0410-aec6-3dcde31c8c00