Revert "remove test"

This reverts commit fa43304.

Author: Rich-Harris

packages/svelte/tests/hydration/samples/ignore-mismatched-href/_config.js

@@ -0,0 +1,19 @@
+import { test } from '../../test';
+
+export default test({
+	server_props: {
+		browser: false
+	},
+
+	props: {
+		browser: true
+	},
+
+	test(assert, target) {
+		assert.equal(target.querySelector('a')?.getAttribute('href'), '/bar');
+	},
+
+	errors: [
+		'The `href` attribute on `<a href="/bar">...</a>` changed its value between server and client renders. The client value, `/foo`, will be ignored in favour of the server value'
+	]
+});

packages/svelte/tests/hydration/samples/ignore-mismatched-href/main.svelte

@@ -0,0 +1,5 @@
+<script>
+	let { browser } = $props();
+</script>
+
+<a href={browser ? '/foo': '/bar'}>foo</a>