More tests for toplevel lexical scope

R=dslomov@chromium.org
BUG=v8:2198
LOG=N

Review URL: https://codereview.chromium.org/716523002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25240 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Removed dead WriteInt32ToHeapNumberStub.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/686883003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25241 ce2b1a6d-e550-0410-aec6-3dcde31c8c00