[gidl][go] Give success cases useful names

Test: fx run-test go_fidl_tests
Change-Id: I0d18b426f25a10d2132326cfe60efc2b22329f93
diff --git a/src/syscall/zx/fidl/fidl_test/testutil_test.go b/src/syscall/zx/fidl/fidl_test/testutil_test.go
index 4bbe287..35e0053 100644
--- a/src/syscall/zx/fidl/fidl_test/testutil_test.go
+++ b/src/syscall/zx/fidl/fidl_test/testutil_test.go
@@ -50,7 +50,7 @@
 }
 
 func (ex encodeSuccessCase) check(t *testing.T) {
-	t.Run("encode", func(t *testing.T) {
+	t.Run(ex.name+" encode", func(t *testing.T) {
 		defer handlePanic(t)
 		b, h, err := encode(ex.input)
 		if err != nil {
@@ -79,7 +79,7 @@
 }
 
 func (ex decodeSuccessCase) check(t *testing.T) {
-	t.Run("decode", func(t *testing.T) {
+	t.Run(ex.name+" decode", func(t *testing.T) {
 		defer handlePanic(t)
 		nbActual, nhActual, output, err := decode(reflect.TypeOf(ex.input), ex.bytes, ex.handles)
 		if err != nil {
@@ -107,15 +107,15 @@
 
 func (ex successCase) check(t *testing.T) {
 	encodeSuccessCase{
-		name: ex.name,
-		input: ex.input,
-		bytes: ex.bytes,
+		name:    ex.name,
+		input:   ex.input,
+		bytes:   ex.bytes,
 		handles: ex.handles,
 	}.check(t)
 	decodeSuccessCase{
-		name: ex.name,
-		input: ex.input,
-		bytes: ex.bytes,
+		name:    ex.name,
+		input:   ex.input,
+		bytes:   ex.bytes,
 		handles: ex.handles,
 	}.check(t)
 }