This is the first built-in function that has an out parameter, so l-value
checks are added for built-ins.

BUG=angle:918

Change-Id: Ifd5befe955224f706f864e25107879c9cdce9e9f
Reviewed-on: https://chromium-review.googlesource.com/250780Tested-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>