[BugFix]add all2all when dp_size > 1 && downgrade npu_dequant_swiglu_quant (#819)

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### What this PR does / why we need it?
1. This PR introduces native `all_to_all` communication operator to fix
`allgather` bugs when dp_size > 1. Besides, it adds a naive
implementation of force-load-balance when doing profile runs.
2. The operator `npu_dequant_swiglu_quant` only supports input
hidden_states with dtype `torch.int32`. This tensor occupies space of
`global_bs * seq_len * topk * hidden_size`, which might be very large as
`ep_size` grows. Therefore we need to disable this operator and use
original `swiglu` && `quantize`.

### Does this PR introduce _any_ user-facing change?
No.

### How was this patch tested?
By performing offline inference:

![image](https://github.com/user-attachments/assets/e003d5dc-0753-41ae-9303-e87f73ac6828)

---------

Signed-off-by: angazenn <zengyanjia@huawei.com>
Co-authored-by: angazenn <zengyanjia@huawei.com>

vllm_ascend/patch/worker/patch_common/patch_distributed.py

@@ -0,0 +1,49 @@
+#
+# Copyright (c) 2025 Huawei Technologies Co., Ltd. All Rights Reserved.
+# This file is a part of the vllm-ascend project.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+from typing import List, Optional
+
+import torch
+import vllm
+from vllm.distributed.parallel_state import GroupCoordinator
+
+
+class GroupCoordinatorPatch(GroupCoordinator):
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+    def all_to_all(self,
+                   input_: torch.Tensor,
+                   scatter_dim: int = 0,
+                   gather_dim: int = -1,
+                   scatter_sizes: Optional[List[int]] = None,
+                   gather_sizes: Optional[List[int]] = None) -> torch.Tensor:
+        if self.world_size == 1:
+            return input_
+        assert -input_.dim() <= scatter_dim < input_.dim(), (
+            f"Invalid scatter dim ({scatter_dim}) for input tensor with shape {input_.size()}"
+        )
+        assert -input_.dim() <= gather_dim < input_.dim(), (
+            f"Invalid gather dim ({gather_dim}) for input tensor with shape {input_.size()}"
+        )
+        return self.device_communicator.all_to_all(input_, scatter_dim,
+                                                   gather_dim, scatter_sizes,
+                                                   gather_sizes)
+
+
+vllm.distributed.parallel_state.GroupCoordinator = GroupCoordinatorPatch  # Note: check the GroupCoordinator with online serving