glapi: Store static dispatch offsets in a separate table

glapi: Store static dispatch offsets in a separate table

Since the set of functions with static will never change, there is no
reason to store it in the XML.  It's just one of those fields that
confuses people adding new functions.

This is split out from the rest of the series so that in-code assertions
can be used to verify that the data in the Python code matches the XML.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Dylan Baker <baker.dylan.c@gmail.com>