don't bail self-invalidation in async mode + don't mark reactions on initial run

not marking without not bailing makes two tests fail, revealing that the "don't self-invalidate in async mode" change would actually be a subtle breaking change

packages/svelte/src/internal/client/reactivity/batch.js

@@ -287,18 +287,20 @@ export class Batch {
 		if (this.#committed) return;
 
 		current_batch = this;
-		this.#started = true;
 
 		if (flush_count++ > 1000) {
 			this.#unlink();
 			infinite_loop_guard();
 		}
 
-		// TODO we only need to do this for re-runs
-		for (const [source, snapshot] of this.current) {
-			mark_reactions(this, source, snapshot.wv, null);
+		if (this.#started) {
+			for (const [source, snapshot] of this.current) {
+				mark_reactions(this, source, snapshot.wv, null);
+			}
 		}
 
+		this.#started = true;
+
 		if (DEV) {
 			// track all the values that were updated during this flush,
 			// so that they can be reset afterwards

packages/svelte/src/internal/client/reactivity/deriveds.js

@@ -1,6 +1,5 @@
-/** @import { Derived, Effect, Reaction, Source, Value } from '#client' */
+/** @import { Derived, Effect, Source, Value } from '#client' */
 /** @import { Batch } from './batch.js'; */
-/** @import { Boundary } from '../dom/blocks/boundary.js'; */
 import { DEV } from 'esm-env';
 import {
 	ERROR_VALUE,
@@ -26,14 +25,13 @@ import {
 	write_version,
 	skipped_deps,
 	new_deps,
-	is_destroying_effect,
-	current_sources
+	is_destroying_effect
 } from '../runtime.js';
 import { equals, safe_equals } from './equality.js';
 import * as e from '../errors.js';
 import * as w from '../warnings.js';
 import { async_effect, destroy_effect, destroy_effect_children, teardown } from './effects.js';
-import { eager_effects, internal_set, set_eager_effects, source, state } from './sources.js';
+import { eager_effects, internal_set, set_eager_effects, state } from './sources.js';
 import { get_error } from '../../shared/dev.js';
 import { async_mode_flag, tracing_mode_flag } from '../../flags/index.js';
 import { component_context } from '../context.js';

packages/svelte/src/internal/client/runtime.js

@@ -300,7 +300,6 @@ export function update_reaction(reaction) {
 		// ensure that if any of those untracked writes result in re-invalidation
 		// of the current effect, then that happens accordingly
 		if (
-			!async_mode_flag &&
 			is_runes() &&
 			untracked_writes !== null &&
 			!untracking &&