vulkan: fix group_norm (#10496)

Fix bad calculation of the end of the range. Add a backend test that
covers the bad case (taken from stable diffusion).

Fixes https://github.com/leejet/stable-diffusion.cpp/issues/439.

ggml/src/ggml-vulkan/vulkan-shaders/group_norm.comp

@@ -19,7 +19,7 @@ void main() {
 
     const uint tid = gl_LocalInvocationID.x;
     const uint start = gl_WorkGroupID.x * group_size + tid;
-    const uint end = start + group_size;
+    const uint end = (gl_WorkGroupID.x + 1) * group_size;
 
     tmp[tid] = 0.0f;