Use device subgroup limits in subgroup_size tests (gpuweb#3885)

src/webgpu/shader/execution/shader_io/compute_builtins.spec.ts

@@ -398,9 +398,11 @@ g.test('subgroup_size')
     t.selectDeviceOrSkipTestCase('subgroups' as GPUFeatureName);
   })
   .fn(async t => {
-    // Replace these with the limits when they are wired up.
-    const minSize = 4;
-    const maxSize = 128;
+    interface SubgroupLimits extends GPUSupportedLimits {
+      minSubgroupSize: number;
+      maxSubgroupSize: number;
+    }
+    const { minSubgroupSize, maxSubgroupSize } = t.device.limits as SubgroupLimits;
 
     const wgx = t.params.sizes[0];
     const wgy = t.params.sizes[1];
@@ -512,7 +514,15 @@ fn main(@builtin(subgroup_size) size : u32,
     });
     const compareData: Uint32Array = compareReadback.data;
 
-    t.expectOK(checkSubgroupSizeConsistency(sizesData, compareData, minSize, maxSize, wgThreads));
+    t.expectOK(
+      checkSubgroupSizeConsistency(
+        sizesData,
+        compareData,
+        minSubgroupSize,
+        maxSubgroupSize,
+        wgThreads
+      )
+    );
   });
 
 /**