PreParser cleanup: no need to track with-ness of scopes.

Historically, we used to track the "with-ness" of a scope differently; not
creating a with scope, but setting a property on the scope (see
https://codereview.chromium.org/5166006 ). For laziness decisions, checking the
with-ness should be unnecessary: the current scope is function scope, and if the
outer scope is global scope, there's surely no with scope in between.

R=ulan@chromium.org
BUG=

Review URL: https://codereview.chromium.org/209863004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20189 ce2b1a6d-e550-0410-aec6-3dcde31c8c00