[MoE Refactor] Move expert map related code into ExpertMapManager class

tests/distributed/test_expert_placement.py

@@ -3,7 +3,9 @@
 
 import pytest
 
-from vllm.model_executor.layers.fused_moe.layer import determine_expert_map
+from vllm.model_executor.layers.fused_moe.expert_map_manager import (
+    determine_expert_map,
+)
 
 
 def verify_round_robin_pattern(expert_map, ep_rank, ep_size, global_num_experts):

tests/kernels/moe/test_moe.py

@@ -1588,7 +1588,7 @@ def test_unquantized_bf16_flashinfer_trtllm_backend(
         layer.apply_router_weight_on_input = False
         layer.routed_scaling_factor = None
         layer.shared_experts = None
-        layer._maybe_init_expert_routing_tables = lambda: None
+        layer._expert_routing_tables = lambda: None
 
         quant_method.process_weights_after_loading(layer)
 

tests/kernels/moe/test_moe_permute_unpermute.py

@@ -10,7 +10,9 @@
 import torch
 
 from vllm.model_executor.layers.fused_moe import fused_topk
-from vllm.model_executor.layers.fused_moe.layer import determine_expert_map
+from vllm.model_executor.layers.fused_moe.expert_map_manager import (
+    determine_expert_map,
+)
 from vllm.model_executor.layers.fused_moe.moe_permute_unpermute import (
     moe_permute,
     moe_permute_unpermute_supported,