Collect type feedback in separate pass and store it in AST

Notes:

- For now, just adds the missing type info fields to the AST nodes directly.
  I'd like to factor that out more nicely in a follow-up CL.

- All type feedback now is uniformly collected through AST nodes'
  RecordTypeFeedback functions. At some point, this logic should be moved
  out of ast.cc.

- The typing pass currently simulates the exact same conditions under
  which feedback was collected in Hydrogen before. That also should be
  made more generic in the future.

- Type information itself is unchanged. Making it more regular is
  yet more future work.

Some additional cleanups:

- Lifted out nested class ObjectLiteral::Property, to enable forward declaration.
- Moved around some auxiliary enums.

R=svenpanne@chromium.org
BUG=

Review URL: https://codereview.chromium.org/14990014

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14825 ce2b1a6d-e550-0410-aec6-3dcde31c8c00