[dart2wasm] Fix web/wasm/flute_stress_test in SDK mode

Currently `web/wasm/flute_stress_test` is failing on
`dart2wasm-linux-optimized-jsc` mode.

That mode runs with `--use-sdk` which makes it use `dart compile wasm`.

The reason the test is failing is because it passes both
`--enable-deferred-loading` and `--multi-module-stress-test` flags to
dart2wasm. This causes us to trigger the deferred module flow instead
of the specialized multi-module flow.

Those two flags should be independent.

Change-Id: I8cac976cd91d4e585f38632ada3062e41fce401f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/458800
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Nate Biggs <natebiggs@google.com>

pkg/dart2wasm/lib/code_generator.dart

@@ -2812,7 +2812,10 @@ abstract class AstCodeGenerator
   }
 
   w.ModuleBuilder? _recognizeDeferredModuleGuard(Let let) {
-    if (!translator.options.enableDeferredLoading) return null;
+    if (!translator.options.enableDeferredLoading &&
+        !translator.options.enableMultiModuleStressTestMode) {
+      return null;
+    }
 
     // TODO(http://dartbug.com/61764): Find better way to do this.
     //

pkg/dart2wasm/lib/kernel_nodes.dart

@@ -437,9 +437,7 @@ mixin KernelNodes {
       index.getTopLevelField('dart:_internal', 'boxedIntImmutableArray');
 
   // Deferred loading.
-  late final Procedure? loadLibraryFromLoadId = index.tryGetProcedure(
-      'dart:_internal', LibraryIndex.topLevel, 'loadLibraryFromLoadId');
-  late final Procedure? checkLibraryIsLoadedFromLoadId = index
+  late final Procedure checkLibraryIsLoadedFromLoadId = index
       .getTopLevelProcedure('dart:_internal', 'checkLibraryIsLoadedFromLoadId');
   late final Procedure? dartInternalLoadingMapGetter = index.tryGetProcedure(
       'dart:_internal', LibraryIndex.topLevel, 'get:_loadingMap');

pkg/dartdev/lib/src/commands/compile.dart

@@ -964,10 +964,11 @@ class CompileWasmCommand extends CompileSubcommandCommand {
       }
     }
 
-    final isMultiModule = args.flag('enable-deferred-loading') ||
-        // Used in testing to force multiple modules.
-        extraCompilerOptions
-            .any((e) => e.contains('enable-multi-module-stress-test'));
+    final isDeferredLoading = args.flag('enable-deferred-loading');
+    // Used in testing to force multiple modules.
+    final isMultiStressTestMode = extraCompilerOptions
+        .any((e) => e.contains('enable-multi-module-stress-test'));
+    final isMultiModule = isDeferredLoading || isMultiStressTestMode;
     final optimizationLevel = int.parse(args.option('optimization-level')!);
 
     final runWasmOpt =
@@ -1012,7 +1013,7 @@ class CompileWasmCommand extends CompileSubcommandCommand {
       if (args.flag('print-kernel')) '--print-kernel',
       if (args.flag(enableAssertsOption.flag)) '--${enableAssertsOption.flag}',
       if (!generateSourceMap) '--no-source-maps',
-      if (isMultiModule) '--enable-deferred-loading',
+      if (isDeferredLoading) '--enable-deferred-loading',
       for (final define in defines) '-D$define',
       if (maxPages != null) ...[
         '--import-shared-memory',