Take all attributes into account when checking for aliasing This makes ANGLE to follow GLSL ES 3.00.6 spec section 12.46. The spec requires that all attributes are taken into account when checking for aliasing, regardless of if they are active or not. WebGL 2.0 spec was also recently changed to reflect GLSL ES 3.00.6 correctly. Aliasing checks for GLSL ES 1.00 shaders are left as-is. BUG=chromium:829541 TEST=angle_end2end_tests, WebGL conformance tests Change-Id: I71c36ac123f18dadf075e81f93af29321c15136b Reviewed-on: https://chromium-review.googlesource.com/1005077 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>