[core] remove beam search from the core (#9105)

vllm/envs.py

@@ -63,7 +63,6 @@ if TYPE_CHECKING:
     VLLM_TORCH_PROFILER_DIR: Optional[str] = None
     VLLM_USE_TRITON_AWQ: bool = False
     VLLM_ALLOW_RUNTIME_LORA_UPDATING: bool = False
-    VLLM_ALLOW_DEPRECATED_BEAM_SEARCH: bool = False
     VLLM_SKIP_P2P_CHECK: bool = False
 
 
@@ -198,10 +197,6 @@ environment_variables: Dict[str, Callable[[], Any]] = {
     lambda: (os.environ.get("VLLM_USE_TRITON_FLASH_ATTN", "True").lower() in
              ("true", "1")),
 
-    # If set, allowing the use of deprecated beam search implementation
-    "VLLM_ALLOW_DEPRECATED_BEAM_SEARCH":
-    lambda: os.environ.get("VLLM_ALLOW_DEPRECATED_BEAM_SEARCH", "0") == "1",
-
     # Internal flag to enable Dynamo graph capture
     "VLLM_TEST_DYNAMO_GRAPH_CAPTURE":
     lambda: int(os.environ.get("VLLM_TEST_DYNAMO_GRAPH_CAPTURE", "0")),