replace snapshot test with runtime test

Author: Rich-Harris

packages/svelte/tests/runtime-runes/samples/store-directive/_config.js

@@ -0,0 +1,6 @@
+import { test } from '../../test';
+
+export default test({
+	html: `<div>mounted</div>`,
+	ssrHtml: `<div>hello</div>`
+});

packages/svelte/tests/runtime-runes/samples/store-directive/main.svelte

@@ -0,0 +1,9 @@
+<script>
+	import { writable } from 'svelte/store';
+
+	let action = writable((node) => {
+		node.textContent = 'mounted';
+	});
+</script>
+
+<div use:$action>hello</div>