add a runtime test, we can always add more later if we need to

Author: Rich-Harris

packages/svelte/tests/runtime-runes/samples/functional-templating/_config.js

@@ -0,0 +1,9 @@
+import { test } from '../../test';
+
+export default test({
+	compileOptions: {
+		templatingMode: 'functional'
+	},
+
+	html: `<p>hello</p>`
+});

packages/svelte/tests/runtime-runes/samples/functional-templating/main.svelte

@@ -0,0 +1 @@
+<p>hello</p>