In some generated shaders, "levels" would be read before it is assigned by GetDimensions when clamping mip level to valid range. Fix these cases. BUG=angleproject:1092 TEST=dEQP-GLES3.functional.shaders.texture_functions.* (12 tests start passing) Change-Id: I9fce8d378606738e5172673d222bce7968e26789 Reviewed-on: https://chromium-review.googlesource.com/312022 Tryjob-Request: Olli Etuaho <oetuaho@nvidia.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Tested-by: Olli Etuaho <oetuaho@nvidia.com>
