[CI] Update UT CANN version to 8.5.0 for main branch (#6564)

### What this PR does / why we need it?
Update UT CANN version to 8.5.0

### Does this PR introduce _any_ user-facing change?
NA


- vLLM version: v0.15.0
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.15.0

---------

Signed-off-by: leo-pony <nengjunma@outlook.com>

setup.py

@@ -334,6 +334,8 @@ class cmake_build_ext(build_ext):
         )
 
     def build_extensions(self) -> None:
+        if not envs.COMPILE_CUSTOM_KERNELS:
+            return
         # Ensure that CMake is present and working
         try:
             subprocess.check_output(["cmake", "--version"])
@@ -423,7 +425,9 @@ except LookupError:
     # only checks out the commit. In this case, we set a dummy version.
     VERSION = "0.0.0"
 
-ext_modules = [CMakeExtension(name="vllm_ascend.vllm_ascend_C")]
+ext_modules = []
+if envs.COMPILE_CUSTOM_KERNELS:
+    ext_modules = [CMakeExtension(name="vllm_ascend.vllm_ascend_C")]
 
 
 def get_path(*filepath) -> str: