ProgramGL: don't bindAttribLocation builtin attributes

BUG=angleproject:1636

Change-Id: Idea0e4f4a4415351b83e8f1a39b697139ff9ebe6
Reviewed-on: https://chromium-review.googlesource.com/414205
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/renderer/gl/ProgramGL.cpp b/src/libANGLE/renderer/gl/ProgramGL.cpp
index 88c7df7..8e7045f 100644
--- a/src/libANGLE/renderer/gl/ProgramGL.cpp
+++ b/src/libANGLE/renderer/gl/ProgramGL.cpp
@@ -148,7 +148,7 @@
         // Bind attribute locations to match the GL layer.
         for (const sh::Attribute &attribute : mState.getAttributes())
         {
-            if (!attribute.staticUse)
+            if (!attribute.staticUse || attribute.isBuiltIn())
             {
                 continue;
             }