[3.14] gh-143706: Fix sys.argv not set during multiprocessing forkserver `__main__...

[3.14] gh-143706: Fix sys.argv not set during multiprocessing forkserver `__main__` preload (GH-143717) (#143763)

gh-143706: Fix sys.argv not set during multiprocessing forkserver `__main__` preload (GH-143717)

The forkserver was not passing sys.argv to its main() function, causing
sys.argv to be empty during `__main__` module import in child processes. This
fixes a non-obvious regression inadvertently introduced by the gh-126631 main
preloading fix.
(cherry picked from commit 298d5440eb83f2dfd5651bac86d1592ec358d54c)

Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com>