chore: more hydration stuff (#10894)

* simplify

* put memory cleanup where it belongs

packages/svelte/src/internal/client/dom/hydration.js

@@ -90,22 +90,9 @@ function get_hydrate_nodes(node, insert_text = false) {
 export function hydrate_block_anchor(node) {
 	if (!hydrating) return;
 
-	if (node.nodeType === 8) {
-		// @ts-ignore
-		let nodes = node.$$fragment;
-		if (nodes === undefined) {
-			nodes = get_hydrate_nodes(node);
-		} else {
-			schedule_task(() => {
-				// @ts-expect-error clean up memory
-				node.$$fragment = undefined;
-			});
-		}
-		set_hydrate_nodes(nodes);
-	} else {
-		const first_child = /** @type {Element | null} */ (node.firstChild);
-		set_hydrate_nodes(first_child === null ? [] : [first_child]);
-	}
+	// @ts-ignore
+	var nodes = node.$$fragment ?? get_hydrate_nodes(node);
+	set_hydrate_nodes(nodes);
 }
 
 /**
@@ -124,6 +111,10 @@ export function capture_fragment_from_node(node) {
 		const target = /** @type {Node} */ (last_child.nextSibling);
 		// @ts-ignore
 		target.$$fragment = nodes;
+		schedule_task(() => {
+			// @ts-expect-error clean up memory
+			target.$$fragment = undefined;
+		});
 		return target;
 	}
 	return node;