port a330af0e (r32539)

  original commit message:
  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=

Review URL: https://codereview.chromium.org/1495803003

Cr-Commit-Position: refs/heads/master@{#32594}