Merge pull request #5887 from yosefe/topic/osc-ucx-fix-finalize-hang-v4.0.x

osc_ucx: fix hang/timeout in component finalize - v4.0

ompi/mca/osc/ucx/osc_ucx_component.c

@@ -822,6 +822,8 @@ int ompi_osc_ucx_free(struct ompi_win_t *win) {
         ucp_worker_progress(mca_osc_ucx_component.ucp_worker);
     }
 
+    opal_common_ucx_worker_flush(mca_osc_ucx_component.ucp_worker);
+
     ret = module->comm->c_coll->coll_barrier(module->comm,
                                              module->comm->c_coll->coll_barrier_module);