Add final barrier to (hopefully) fix windows

Author: LegNeato

tests/difftests/tests/arch/workgroup_memory/workgroup_memory-rust/src/lib.rs

@@ -66,6 +66,10 @@ pub fn main_cs(
         shared[lid] += shared[lid + 1];
     }
 
+    unsafe {
+        workgroup_memory_barrier_with_group_sync();
+    }
+
     // Write final result
     if lid == 0 {
         output[0] = shared[0];

tests/difftests/tests/arch/workgroup_memory/workgroup_memory-wgsl/shader.wgsl

@@ -52,6 +52,8 @@ fn main_cs(@builtin(local_invocation_id) local_id: vec3<u32>) {
         shared_data[lid] += shared_data[lid + 1u];
     }
 
+    workgroupBarrier();
+    
     // Write final result
     if (lid == 0u) {
         output[0] = shared_data[0];