Visual Studio 2015 generates an error for using array_lengthof() on
a template class member array. Since the array content does not
depend on the template types, just make it a global.

BUG=swiftshader:7

Change-Id: If197308413f880484be06e6738f246be144d0ba6
Reviewed-on: https://chromium-review.googlesource.com/380501Reviewed-by: Jim Stichnoth <stichnot@chromium.org>
Tested-by: Nicolas Capens <nicolascapens@google.com>