[Refactor]refactor 310p ops and add ut (#6591)

### What this PR does / why we need it?
This pull request focuses on a significant refactoring effort within the
vllm-ascend project, specifically targeting operations optimized for the
Ascend 310P hardware. The changes aim to streamline the implementation
of core components like quantization and multi-head attention, making
the codebase more maintainable and robust. Concurrently, new unit tests
have been introduced to ensure the correctness and reliability of these
refactored modules.

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

### How was this patch tested?
E2E test with qwen3-32b w8a8

- vLLM version: v0.15.0
- vLLM main:
d7e17aaacd

---------

Signed-off-by: pu-zhe <zpuaa@outlook.com>

vllm_ascend/_310p/quantization/methods/w8a8_static.py

@@ -26,7 +26,7 @@ from .registry import register_scheme
 
 
 @register_scheme("W8A8", "linear")
-class AscendW8A8LinearMethod310P(AscendLinearScheme):
+class AscendW8A8LinearMethod310(AscendLinearScheme):
     """310P-only W8A8 static linear scheme.
 
     Notes:

vllm_ascend/_310p/quantization/modelslim_config.py

@@ -46,7 +46,7 @@ from vllm_ascend.utils import ASCEND_QUANTIZATION_METHOD
 logger = init_logger(__name__)
 
 
-def create_scheme_for_layer_310p(
+def create_scheme_for_layer(
     cfg: AscendModelSlimConfig,
     quant_description: dict[str, Any],
     prefix: str,
@@ -140,7 +140,7 @@ class AscendModelSlimConfig310(AscendModelSlimConfig):
 
                 return AscendUnquantizedLinearMethod()
 
-            scheme = create_scheme_for_layer_310p(
+            scheme = create_scheme_for_layer(
                 cfg=self,
                 quant_description=self.quant_description,
                 prefix=prefix,