Fix a bug in the calculation of stack uniformity

* The simulation incorrectly marked some continues as non-uniform
  * this leads to some ballots being marked with the special value
  * in WGSLv1, Workgroup, and Subgroup styles this would lead to fewer
    ballots being checked (so likely no change in results)
  * in Maximal though, this leads to some ballots being a wacky value
    and extra failures

src/webgpu/shader/execution/reconvergence/util.ts

@@ -1966,7 +1966,7 @@ ${this.functions[i]}`;
             break;
           }
 
-          const uniform = this.style === Style.WGSLv1 && this.isUniform(mask, subgroupSize);
+          const uniform = this.style !== Style.WGSLv1 || this.isUniform(mask, subgroupSize);
 
           let n = nesting;
           for (; n >= 0; n--) {