remove an irrelevant test from test_modeling_tf_layoutlm

[ydshieh]

What does this PR do?

This PR remove test_model_various_embeddings from test_modeling_tf_layoutlm.py.

More Information

Current version of test_modeling_tf_layoutlm.py has

def test_model_various_embeddings(self):
    config_and_inputs = self.model_tester.prepare_config_and_inputs()
    for type in ["absolute", "relative_key", "relative_key_query"]:
        config_and_inputs[0].position_embedding_type = type
        self.model_tester.create_and_check_model(*config_and_inputs)

After a quick search inside the repo, I believe position_embedding_type is only for (some) PyTorch models, and test_model_various_embeddings is not necessary here. Furthermore,

• test_modeling_tf_layoutlm.py is the only TF test script containing position_embedding_type
• modeling_tf_layoutlm.py has no usage of config.position_embedding_type.

Therefore, this PR remove test_model_various_embeddings from test_modeling_tf_layoutlm.py.

[LysandreJik]

Indeed, good catch @ydshieh!