[Torch 2.11] Guard torch._C._cpu attribute checks for forward compatibility (#35673)

Signed-off-by: atalman <atalman@fb.com>

benchmarks/kernels/cpu/benchmark_cpu_attn.py

@@ -27,7 +27,7 @@ def get_attn_isa(
     else:
         if current_platform.get_cpu_architecture() == CpuArchEnum.ARM:
             return "neon"
-        elif torch._C._cpu._is_amx_tile_supported():
+        elif torch.cpu._is_amx_tile_supported():
             return "amx"
         else:
             return "vec"

benchmarks/kernels/cpu/benchmark_cpu_fused_moe.py

@@ -24,7 +24,7 @@ except (ImportError, AttributeError) as e:
     sys.exit(1)
 
 # ISA selection following test_cpu_fused_moe.py pattern
-ISA_CHOICES = ["amx", "vec"] if torch._C._cpu._is_amx_tile_supported() else ["vec"]
+ISA_CHOICES = ["amx", "vec"] if torch.cpu._is_amx_tile_supported() else ["vec"]
 
 
 @torch.inference_mode()