GL_MAX_RECTANGLE_TEXTURE_SIZE_ARB was getting queried by Chromium
since GL_ARB_texture_rectangle is exposed, and if this query fails,
WebGL does not get enabled.

Change-Id: Ie6b40f35f0cfc4547079e303609afa3778010dd1
Reviewed-on: https://swiftshader-review.googlesource.com/16849Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Alexis Hétu <sugoi@google.com>