GLES1: glMultiTexCoord4(f|x) BUG=angleproject:2306 + common validation for multitexturing units + clang-format Change-Id: I6eb456c273490e85fc7008e7e11d15e22dd20276 Reviewed-on: https://chromium-review.googlesource.com/987298 Commit-Queue: Lingfeng Yang <lfy@google.com> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>