Reason for revert:
Tanks EarleyBoyer.
Original issue's description:
> [compiler] Properly guard the speculative optimizations for instanceof.
>
> Add a general feedback slot for instanceof similar to what we already have
> for for-in, which basically has a fast (indicated by the uninitialized
> sentinel) and a slow (indicated by the megamorphic sentinel) mode. Now
> we can only take the fast path when the feedback slot says it hasn't
> seen any funky inputs and nothing funky appeared in the prototype chain.
> In the TurboFan code we also deoptimize whenever we see a funky object
> (i.e. a proxy or an object that requires access checks) in the prototype
> chain (similar to what Crankshaft already did).
>
> Drive-by-fix: Also make Crankshaft respect the mode and therefore
> address the deopt loop in Crankshaft around instanceof.
>
> We might want to introduce an InstanceOfIC mechanism at some point and
> track the map of the right-hand side.
>
> BUG=v8:5267
> R=mvstanton@chromium.org
>
> Committed: https://crrev.com/a0484bc6116ebc2b855de87d862945e2ae07169b
> Cr-Commit-Position: refs/heads/master@{#39718}
TBR=mvstanton@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5267
Review-Url: https://codereview.chromium.org/2365223003
Cr-Commit-Position: refs/heads/master@{#39736}
b9cdb630dd