This switches the {ParseInfo} constructor to always determine the outer
scope info from the shared function info instead of a concrete closure.
It is a precursor to deprecate the constructor taking closures entirely
and hence make the fact that we can parse without a closure explicit.

R=jochen@chromium.org
BUG=v8:2206

Review-Url: https://codereview.chromium.org/2397053003
Cr-Commit-Position: refs/heads/master@{#40031}