[BugFix] Fix `assert x_s.shape[-1] == x_q.shape[-1] // group_shape[1]` in...

[BugFix] Fix `assert x_s.shape[-1] == x_q.shape[-1] // group_shape[1]` in Blackwell Quantized MoE Test (#32362)
Signed-off-by: Lucas Wilkinson <lwilkins@redhat.com>
Signed-off-by: Lucas Wilkinson <LucasWilkinson@users.noreply.github.com>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

vllm/model_executor/layers/quantization/utils/quant_utils.py

@@ -247,8 +247,8 @@ def scaled_dequantize(
     if group_shape is not None:
         group_shape = _normalize_quant_group_shape(x_q, group_shape)
 
-    if x_s.ndim == 0:  # scalar
-        x_s = x_s.unsqueeze(-1).unsqueeze(-1)  # convert to (1, 1) tensor
+    if x_s.numel() == 1:  # scalar
+        x_s = x_s.reshape(1, 1)  # normalize all scalar-like tensors to (1, 1)
     if x_s.ndim == 1:
         if group_shape is None:
             raise AssertionError(