Fix test: "unknown case statement" from spirv reader

Bug found when passing program through spirv writer and then reader.

Bug: tint:792
Change-Id: I904b959ba1d540b4377f8b9027286182ee0c34e9
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/50561
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
diff --git a/src/resolver/resolver_test.cc b/src/resolver/resolver_test.cc
index fcfde03..5464105 100644
--- a/src/resolver/resolver_test.cc
+++ b/src/resolver/resolver_test.cc
@@ -83,7 +83,9 @@
   ast::CaseSelectorList lit;
   lit.push_back(create<ast::SintLiteral>(3));
   auto* cse = create<ast::CaseStatement>(lit, block);
-  WrapInFunction(v, cse);
+  auto* cond_var = Var("c", ty.i32(), ast::StorageClass::kFunction);
+  auto* sw = Switch(cond_var, cse, DefaultCase());
+  WrapInFunction(v, cond_var, sw);
 
   EXPECT_TRUE(r()->Resolve()) << r()->error();