[Bugfix] fix custom op GmmSwigluQuantWeightNzTensorList (#4593)

### What this PR does / why we need it?

1. Fixes the environment path used to locate custom op shared libraries.
2. Uses empty tensor initialization for op outputs instead of
zero-initialization for better efficiency.



- vLLM version: v0.11.2
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.2

---------

Signed-off-by: QianChenxi <chenxi.qian.cq@outlook.com>

vllm_ascend/platform.py

@@ -38,27 +38,6 @@ from vllm_ascend.utils import (
     prefill_context_parallel_enable, update_aclgraph_sizes,
     update_cudagraph_capture_sizes, update_default_aclgraph_sizes)
 
-# set custom ops path
-CUR_DIR = os.path.dirname(os.path.realpath(__file__))
-CUSTOM_OPP_PATH = os.path.join(CUR_DIR, "vllm_ascend", "_cann_ops_custom",
-                               "vendors", "customize")
-CUSTOM_LIB_PATH = os.path.join(CUSTOM_OPP_PATH, "op_api", "lib")
-
-if os.path.exists(CUSTOM_OPP_PATH):
-    current_cust_opp_path = os.environ.get("ASCEND_CUSTOM_OPP_PATH", "")
-    if current_cust_opp_path:
-        os.environ[
-            "ASCEND_CUSTOM_OPP_PATH"] = f"{CUSTOM_OPP_PATH}:{current_cust_opp_path}"
-    else:
-        os.environ["ASCEND_CUSTOM_OPP_PATH"] = CUSTOM_OPP_PATH
-
-if os.path.exists(CUSTOM_LIB_PATH):
-    current_lib_path = os.environ.get("LD_LIBRARY_PATH", "")
-    if current_lib_path:
-        os.environ["LD_LIBRARY_PATH"] = f"{CUSTOM_LIB_PATH}:{current_lib_path}"
-    else:
-        os.environ["LD_LIBRARY_PATH"] = CUSTOM_LIB_PATH
-
 if TYPE_CHECKING:
     from vllm.config import ModelConfig, VllmConfig
     from vllm.utils import FlexibleArgumentParser