When we try to get a function literal with an ID beyond the
last known ID we easily create out-of-bound read bugs. It's preferable
to crash in this situation.

BUG=chromium:789764
R=marja@chromium.org

Change-Id: I4f35e9231ef6af18204bbac96df3652c3d30c29f
Reviewed-on: https://chromium-review.googlesource.com/798411Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Jochen Eisinger <jochen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49738}