Make trailing comma test not dependent on exact group contents.

This allows us to change what the last item is without breaking the test.

It does still test the intended thing, because it requires that the trailing comma come before the closing `}` token.

PiperOrigin-RevId: 509487102
diff --git a/rs_bindings_from_cc/ir_matchers.rs b/rs_bindings_from_cc/ir_matchers.rs
index e26cab2..4202ee7 100644
--- a/rs_bindings_from_cc/ir_matchers.rs
+++ b/rs_bindings_from_cc/ir_matchers.rs
@@ -145,7 +145,7 @@
     fn test_assert_ir_matches_assumes_trailing_commas_in_groups() {
         assert_ir_matches!(
             ir_from_cc("").unwrap(),
-            quote! {{... crate_root_path: None, }}
+            quote! {{... , }}
         );
     }