This makes sure that proxy + Function/Array works
Makes sure that new.target can be a generator
Makes sure that if new.target is not a subclass, but does not have a prototype, that we'll get that same prototype back the next time we look at new.target.prototype.

BUG=v8:1543, v8:3330, v8:3931
LOG=n

Review URL: https://codereview.chromium.org/1484473002

Cr-Commit-Position: refs/heads/master@{#32382}