Instead having the proc table be generated from proc_table_data.json
which needed to be manually updated with changes, the proc table is now
generated from data in gl.xml and egl.xml

Bug: angleproject:3533
Change-Id: I773ea7615cc4ec1c9901def629b089d8d17328eb
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1660645
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>