test: add guard-derived short-circuit regression

Author: LeeWxx

packages/svelte/tests/runtime-runes/samples/guard-derived-short-circuit/_config.js

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+import { test } from '../../test';
+import { flushSync } from 'svelte';
+
+export default test({
+	mode: ['client'],
+	async test({ target, assert }) {
+		const button = target.querySelector('button');
+
+		flushSync(() => button?.click());
+
+		assert.equal(target.textContent?.trim(), 'Trigger');
+	}
+});

packages/svelte/tests/runtime-runes/samples/guard-derived-short-circuit/main.svelte

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+<script>
+	let virtualItems = $state([{ index: 0 }, { index: 1 }, { index: 2 }]);
+	let centerRows = $state([{ depth: 2 }, { depth: 1 }, { depth: 1 }]);
+
+	let someChange = $state(false);
+	$effect(() => {
+		if (someChange) centerRows = [];
+	});
+</script>
+
+{#each virtualItems as row (row.index)}
+	{@const centerRow = centerRows[row.index]}
+	{#if centerRow != undefined && centerRow.depth != undefined && typeof centerRow === "object" && "depth" in centerRow && typeof centerRow.depth === "number"}
+		{#if centerRow.depth != undefined && centerRow.depth > 0}
+			Hello World<br />
+		{/if}
+	{/if}
+{/each}
+
+<button onclick={() => (someChange = true)}>Trigger</button>