[dart2wasm] Fix return in load ID module compile loop.

The 'return' on line 213 was causing only the first module to be
compiled.

The updated deferred_loading test now guards against this error.

Change-Id: Idfc1583bc4facbfe70f291797084a913f6fc4525
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/455380
Reviewed-by: Mayank Patke <fishythefish@google.com>
Commit-Queue: Nate Biggs <natebiggs@google.com>

Author: natebiggs

pkg/dart2wasm/lib/js/runtime_blob.dart

@@ -194,7 +194,7 @@ final moduleLoadingHelperTemplate = Template(r'''
         const module = await ((source instanceof Response)
             ? WebAssembly.compileStreaming(source, this.builtins)
             : WebAssembly.compile(source, this.builtins));
-        return await WebAssembly.instantiate(module, {
+        await WebAssembly.instantiate(module, {
           ...baseImports,
           ...additionalImports,
           <<JS_POLYFILL_IMPORT>>
@@ -210,7 +210,7 @@ final moduleLoadingHelperTemplate = Template(r'''
           const module = await ((source instanceof Response)
               ? WebAssembly.compileStreaming(source, this.builtins)
               : WebAssembly.compile(source, this.builtins));
-          return await WebAssembly.instantiate(module, {
+          await WebAssembly.instantiate(module, {
             ...baseImports,
             ...additionalImports,
             <<JS_POLYFILL_IMPORT>>

pkg/dart2wasm/test/deferred_loading/data/b.dart

@@ -2,6 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'd.dart';
+
 void b() {
   print('In b');
+  d();
 }

pkg/dart2wasm/test/deferred_loading/data/c.dart

@@ -2,6 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'd.dart';
+
 void c() {
   print('In c');
+  d();
 }

pkg/dart2wasm/test/deferred_loading/data/d.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+void d() {
+  print('In d');
+}

pkg/dart2wasm/test/deferred_loading/data/deferred_load_ids.golden.json

@@ -3,10 +3,11 @@
     "name": "<unnamed>",
     "imports": {
       "1": [
-        "out_module2.wasm"
+        "out_module3.wasm"
       ],
       "2": [
-        "out_module1.wasm"
+        "out_module1.wasm",
+        "out_module2.wasm"
       ]
     },
     "importPrefixToLoadId": {
@@ -18,10 +19,12 @@
     "name": "<unnamed>",
     "imports": {
       "3": [
-        "out_module1.wasm"
+        "out_module1.wasm",
+        "out_module2.wasm"
       ],
       "4": [
-        "out_module3.wasm"
+        "out_module2.wasm",
+        "out_module4.wasm"
       ]
     },
     "importPrefixToLoadId": {