Drop the abrupt-exit-code reporting from the 3.14 backport

Reporting the exit codes of processes that died without a known cause
is a new feature, not part of the gh-101267 bugfix. Keep only the
bugfix on 3.14: each failed future gets its own BrokenProcessPool
exception instead of one shared instance.

Author: gpshead

Lib/concurrent/futures/process.py

@@ -472,22 +472,9 @@ def _terminate_broken(self, cause):
         # All pending tasks are to be marked failed with a
         # BrokenProcessPool error, as separate instances to avoid sharing
         # a traceback (gh-101267).
-        cause_str = None
+        cause_tb = None
         if cause is not None:
-            cause_str = ''.join(cause)
-        else:
-            # No cause known, so report any processes that have
-            # terminated with nonzero exit codes, e.g. from a
-            # segfault. Multiple may terminate simultaneously,
-            # so include all of them in the traceback.
-            errors = []
-            for p in self.processes.values():
-                if p.exitcode is not None and p.exitcode != 0:
-                    errors.append(f"Process {p.pid} terminated abruptly "
-                                  f"with exit code {p.exitcode}")
-            if errors:
-                cause_str = "\n".join(errors)
-        cause_tb = f"\n'''\n{cause_str}'''" if cause_str else None
+            cause_tb = f"\n'''\n{''.join(cause)}'''"
 
         # Mark pending tasks as failed.
         for work_id, work_item in self.pending_work_items.items():