This reduces code duplication in a few generator scripts. The version
lists are now located in registry_xml.

Bug: angleproject:2621
Change-Id: Ia1470f2863753d78d8def1132a20e81d3f8ec4a3
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2566591Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Tim Van Patten <timvp@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>