Casting -32767.0f to uint16_t on Android resulted in 0.
According to C99 6.3.1.4 footnote 50 this kind of cast behavior is unspecified

BUG=angleproject:913
TEST=build/android/test_runner.py gtest -s angle_unittests --release

Change-Id: I136386fe0aa618c17f07f99d8e1ca72fa407d36a
Reviewed-on: https://chromium-review.googlesource.com/323230
Tryjob-Request: Yuly Novikov <ynovikov@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tryjob-Request: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Tested-by: Yuly Novikov <ynovikov@chromium.org>