When calling into C++ builtins, we need to make sure that the argument
count register contains the correct number of arguments, otherwise the
CEntryStub will not be able to leave the stack in the correct state.

R=ishell@chromium.org
BUG=v8:4413
LOG=n

Review URL: https://codereview.chromium.org/1391543002

Cr-Commit-Position: refs/heads/master@{#31120}