update tests

test/runtime/samples/dev-warning-missing-data-binding/main.svelte

@@ -1,5 +1,6 @@
 <script>
 	export let value;
+	export let value_with_default = undefined;
 </script>
 
 <input bind:value>

test/runtime/samples/dev-warning-missing-data-component/Foo.svelte

@@ -1,6 +1,7 @@
 <script>
 	export let x;
 	export let y;
+	export let z = undefined;
 </script>
 
 <div>{x} {y}</div>