fix gr00t checkpoint portability (#1219) #128

Job	Run time
MetaX tests / checkout_and_config	6s
CUDA tests	-1s
check_docker_changes	-10s
MetaX tests / cli_validation / functional_test_cli	42s
MetaX tests / unit_tests (c550) / unit-c550	3m 33s
MetaX tests / functional_tests_train / functional_test_train (c550, train, qwen3, 0_6b_metax)	5m 9s
MetaX tests / functional_tests_benchmark	0s
MetaX tests / functional_tests_inference	0s
MetaX tests / functional_tests_hetero_train	0s
MetaX tests / functional_tests_serve	0s
MetaX tests / all_tests_complete	3s
all_tests	5s
	9m 27s

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