[3.13] gh-98552: Revert (unneeded, already done elsewhere) "flush std streams in the multiprocessing forkserver before fork (GH-141849)" (GH-141871) (#141873)

gh-98552: Revert (unneeded, already done elsewhere) "flush std streams in the multiprocessing forkserver before fork (GH-141849)" (GH-141871)

Revert (unneeded, already done elsewhere) "gh-98552: flush std streams in the multiprocessing forkserver before fork (GH-141849)"

This reverts commit 58badb1711.
(cherry picked from commit 614a28b3da)

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

Lib/multiprocessing/forkserver.py

@@ -270,7 +270,6 @@ def main(listener_fd, alive_r, preload, main_path=None, sys_path=None):
                                     len(fds)))
                         child_r, child_w, *fds = fds
                         s.close()
-                        util._flush_std_streams()
                         pid = os.fork()
                         if pid == 0:
                             # Child

Misc/NEWS.d/next/Library/2025-11-22-18-00-38.gh-issue-98552.d5KNy-.rst

@@ -1,4 +0,0 @@
-The :mod:`multiprocessing` forkserver process now flushes stdout and stderr
-before it forks to avoid the confusion children inheriting any buffered but
-not yet written output data.  Normally there is none, but when using
-:func:`multiprocessing.set_forkserver_preload` there *could* be.