after_qed: refrain from Position.setmp_thread_data, which causes duplication of results with several independent proof attempts;
after_qed: refrain from Position.setmp_thread_data, which causes duplication of results with several independent proof attempts;

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle