coverage85-step2d: 新测试 lint 清理（删无用导入与变量）

deploy/tests/test_coverage85_verify_multiuser.py

@@ -24,6 +24,7 @@ sys.path.insert(0, str(REPO_ROOT))
 _SPEC = importlib.util.spec_from_file_location(
     "verify_multiuser",
     os.path.join(REPO_ROOT, "deploy", "verify-multiuser.py"))
+assert _SPEC is not None and _SPEC.loader is not None
 vm = importlib.util.module_from_spec(_SPEC)
 _SPEC.loader.exec_module(vm)