This widens the range of value output counts to 32 bit on the {Operator}
class. Note that the limit imposed by the parser is 65535 parameters for
each function, but the {Start} node has additional value outputs.

R=jarin@chromium.org
TEST=mjsunit/regress/regress-crbug-724153
BUG=chromium:724153

Change-Id: I21b5d947cc2305b255ddbbff6ec1dfa5c02784c7
Reviewed-on: https://chromium-review.googlesource.com/517489Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45573}