Fix querying large vertex attrib divisors glGetVertexAttribIuiv previously returned an incorrect value for GL_VERTEX_ATTRIB_ARRAY_DIVISOR, because the divisor was treated as an integer even though it is an unsigned integer. BUG=angleproject:2281 Change-Id: I4d1c9df15244db855c6a000fc8fb6cc786bfcb85 Reviewed-on: https://chromium-review.googlesource.com/c/1273300 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>