IEEE rules for generating zero or infinity are now checked for the
constant folding of several built-in functions except for the cases
where ESSL 3.00.6 explicitly states that the results are undefined.

BUG=chromium:661857
TEST=angle_unittests

Change-Id: I2ce427229a5583039694d060ea6db29c5bdace97
Reviewed-on: https://chromium-review.googlesource.com/414370Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>