ArgumentsAdaptorStub for derived constructor (the one that needs
new.target) works in this way:
 - If the constructor is invoked via the Construct stub, we know that
   actual arguments always include new.target. ``arguments`` object
   however should not include a new.target, therefore we remove it.
   We achieve this by decrementing the argument count.
 - If the constructor is invoked as a call, we do not care for a correct
   ``arguments`` array since the constructor will immediately throw on
   entrance.
The bug is that the call could actually pass 0 actual arguments, but I
decrement unconditionally :(. The fix is to detect this case and avoid
decrementing. ``arguments`` is bogus, but it is ok as constructor
throws.

Long-term we should just remove mucking about with arguments for
new.target and just get it from the stack.

R=arv@chromium.org,rossberg@chromium.org
BUG=chromium:474783
LOG=Y

Review URL: https://codereview.chromium.org/1126783003

Cr-Commit-Position: refs/heads/master@{#28242}