Support multi-arch cpu_arch in py_config and schedulable_nodes

Store cpu_arch as list in py_config for multi-arch runs. Fix
schedulable_nodes to normalize cpu_arch to list and use 'in' membership
check. Update cluster info log to handle list cpu_arch display.

Signed-off-by: Harel Meir <hmeir@redhat.com>
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: hmeir

utilities/pytest_utils.py

@@ -598,6 +598,7 @@ def update_cpu_arch_related_config(cpu_arch_option: str) -> None:
     cpu_arch = cpu_arch_option.split(",") if cpu_arch_option else list(get_cluster_architecture())
 
     if len(cpu_arch) > 1:
+        py_config["cpu_arch"] = cpu_arch  # stored as list for multiarch runs
         LOGGER.warning("OS matrix generation is not supported for multi-arch runs!")
     else:
         arch = cpu_arch[0]

utilities/unittests/test_pytest_utils.py

@@ -1890,7 +1890,7 @@ def test_multi_arch_option_logs_warning(
             mock_logger.warning.assert_called_once_with("OS matrix generation is not supported for multi-arch runs!")
             mock_generate_common.assert_not_called()
             mock_generate_instance.assert_not_called()
-            assert "cpu_arch" not in mock_py_config
+            assert mock_py_config["cpu_arch"] == ["amd64", "arm64"]
 
     @patch("utilities.pytest_utils.generate_instance_type_matrix_dicts")
     @patch("utilities.pytest_utils.generate_common_template_matrix_dicts")
@@ -2115,7 +2115,7 @@ def test_three_arch_option_logs_warning(
             mock_logger.warning.assert_called_once_with("OS matrix generation is not supported for multi-arch runs!")
             mock_generate_common.assert_not_called()
             mock_generate_instance.assert_not_called()
-            assert "cpu_arch" not in mock_py_config
+            assert mock_py_config["cpu_arch"] == ["amd64", "arm64", "s390x"]
 
     @patch("utilities.pytest_utils.generate_instance_type_matrix_dicts")
     @patch("utilities.pytest_utils.generate_common_template_matrix_dicts")