kevm-pyk/__main__: close rpc server upon stepping into worker thread

Author: ehildenb

kevm-pyk/src/kevm_pyk/__main__.py

@@ -445,6 +445,7 @@ def prove_it(id_cfg_port: Tuple[str, Tuple[KCFG, Path], int]) -> bool:
             return False
 
     with ProcessPool(ncpus=workers) as process_pool:
+        foundry.close_kore_rpc()
         proof_problems = [(k, v, 3010 + i) for i, (k, v) in enumerate(kcfgs.items())]
         results = process_pool.map(prove_it, proof_problems)
         process_pool.close()