Fix system semantics of SV_GroupIndex (shader-slang#5496)

Close the issue shader-slang#4940.

Author: kaizhangNV

source/slang/slang-ir-wgsl-legalize.cpp

@@ -154,6 +154,13 @@ WGSLSystemValueInfo LegalizeWGSLEntryPointContext::getSystemValueInfo(
         }
         break;
 
+    case SystemValueSemanticName::GroupIndex:
+        {
+            result.wgslSystemValueName = toSlice("local_invocation_index");
+            result.permittedTypes.add(builder.getUIntType());
+        }
+        break;
+
     default:
         {
             m_sink->diagnose(

tests/compute/texture-simpler.slang

@@ -5,7 +5,7 @@
 //TEST(smoke,compute, vulkan):COMPARE_COMPUTE_EX:-vk -compute -shaderobj -output-using-type -render-feature hardware-device
 //TEST(smoke,compute):COMPARE_COMPUTE_EX:-cuda -compute  -shaderobj -output-using-type
 //TEST(smoke,compute):COMPARE_COMPUTE:-slang -shaderobj -mtl -output-using-type
-//DISABLE_TEST(compute):COMPARE_COMPUTE:-slang -shaderobj -wgpu
+//TEST(smoke,compute):COMPARE_COMPUTE:-wgpu -slang -compute -shaderobj -output-using-type
 
 //TEST_INPUT: Texture2D(size=4, content = one):name t2D
 Texture2D<float> t2D;