Clear the list of shared function infos attached to a script before
compiling for live edit in order to avoid duplicates. This was lost in
058deb27. Additionally, we restore the
original list of shared function infos once we're done with live edit
work.

R=yangguo@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/1969293003
Cr-Commit-Position: refs/heads/master@{#36200}