Tune context allocation for variables accessed from inner scopes.

Tune context allocation for variables accessed from inner scopes.

After introduction of with scopes we have enough static information to omit
context allocation in the case that a variable is accessed from a nested block
or catch scope of the same function. Only variables accessed from the inside of
a nested function or with scope are forced to be allocated in the context.

This essentially reverts
http://code.google.com/p/v8/source/detail?r=9281 .
which in turn reverted an earlier change.

Review URL: http://codereview.chromium.org/8431001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9872 ce2b1a6d-e550-0410-aec6-3dcde31c8c00