[CI]: Add core_model and cpu markers for L1 use case. (#1709)

Signed-off-by: zhumingjue <zhumingjue@huawei.com>

tests/diffusion/models/nextstep_1_1/test_nextstep_cfg_parallel_layout.py

@@ -8,6 +8,8 @@ import vllm_omni.diffusion.models.nextstep_1_1.pipeline_nextstep_1_1 as nextstep
 from vllm_omni.diffusion.models.nextstep_1_1.modeling_nextstep_heads import FlowMatchingHead
 from vllm_omni.diffusion.models.nextstep_1_1.pipeline_nextstep_1_1 import NextStep11Pipeline
 
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
 
 class _DummyImageHead:
     def __init__(self, token_dim: int):

tests/diffusion/models/z_image/test_zimage_tp_constraints.py

@@ -2,6 +2,8 @@ import pytest
 
 from vllm_omni.diffusion.models.z_image.z_image_transformer import validate_zimage_tp_constraints
 
+pytestmark = [pytest.mark.core_model, pytest.mark.cpu]
+
 
 def test_validate_zimage_tp_constraints_tp2_ok():
     ffn_hidden_dim, final_out_dims, supported_tp = validate_zimage_tp_constraints(