The optimized code generated by Crankshaft cannot properly deal
with proxies (in the prototype chain), and there's probably no
point in trying to make that work^Wfast with Crankshaft at all.
TurboFan will handle that properly; Crankshaft just bails out
to fullcodegen, which then goes to the runtime, which should do
the right thing soon.

BUG=v8:1543
LOG=n

Review URL: https://codereview.chromium.org/1492983002

Cr-Commit-Position: refs/heads/master@{#32539}