Minor LookupIterator cleanups

BUG=
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/480283003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23348 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Clean up LookupIterator::Configuration naming

BUG=
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/503663003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23349 ce2b1a6d-e550-0410-aec6-3dcde31c8c00