A build wrapper's rc=143 may mean it was killed after the build succeeded

If you SIGTERM a build-queue job (e.g. to free the machine for a priority build), the wrapper can record FAIL rc=143 even though the underlying build already finished. Killing the wrapper's bash doesn't necessarily kill its child xcodebuild either, which keeps running orphaned (PPID 1) and holds the shared DerivedData. Before you requeue, read the tail of the job's own log for the tool's success line, and kill orphaned children by PID. Record the corrected result so reviewers don't rebuild for nothing.