Fixes for improved exist instance

theories/hocap/concurrent_runners.v

theories/lecture_notes/lists.v

theories/locks/array_based_queuing_lock/abql.v

theories/logatom/conditional_increment/cinc.v

theories/logatom/counter_with_backup/counter_proof.v

theories/logatom/herlihy_wing_queue/hwq.v

...s/logrel/F_mu_ref_conc/binary/examples/stack/refinement.v

theories/spanning_tree/spanning.v