ESSL3.00 and 3.10 specs don't allow even newlines before the version
directive.

BUG=angleproject:1009
TEST=WebGL 2 conformance tests, angle_unittests

Change-Id: Id7967829077e35e03572c724e0eafffbed0c975b
Reviewed-on: https://chromium-review.googlesource.com/272719Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>