tests: runtime: recusive each block with function conditional

Add a test to detect issue #4120.

test/runtime/samples/each-block-recursive-with-function-condition/_config.js

@@ -0,0 +1,8 @@
+export default {
+	html: `
+		<p>OK</p>
+		<p>OK</p>
+		<pre>one</pre>
+		<pre>two</pre>
+	`
+};

test/runtime/samples/each-block-recursive-with-function-condition/main.svelte

@@ -0,0 +1,13 @@
+<script>
+let a = () => true;
+export let data = [{ foo: [{ foo: [{bar: "one"}, {bar: "two"}] }] }];
+</script>
+
+{#each data as datum}
+	{#if datum.foo && a()}
+		<p>OK</p>
+		<svelte:self data={datum.foo}/>
+	{:else}
+		<pre>{datum.bar}</pre>
+	{/if}
+{/each}