gh-108740: Fix "make regen-all" race condition (#108741)

gh-108740: Fix "make regen-all" race condition (#108741)

Fix a race condition in "make regen-all". The deepfreeze.c source and
files generated by Argument Clinic are now generated or updated
before generating "global objects". Previously, some identifiers may
miss depending on the order in which these files were generated.

* "make regen-global-objects": Make sure that deepfreeze.c is
  generated and up to date, and always run "make clinic".
* "make clinic" no longer runs generate_global_objects.py script.
* "make regen-deepfreeze" now only updates deepfreeze.c (C file).
  It doesn't build deepfreeze.o (object) anymore.
* Remove misleading messages in "make regen-global-objects" and
  "make clinic". They are now outdated, these commands are now
  safe to use.
* Document generates files in Doc/using/configure.rst.

Co-authored-by: Erlend E. Aasland <erlend@python.org>