[vm/aot] Disable bytecode in AOT compilation pipeline

This is needed for the next D27 release.

Change-Id: I199ac701cb140dc84bb723d232c1b408088b1fe2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/124469
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>

Author: alexmarkov

pkg/frontend_server/lib/frontend_server.dart

@@ -133,7 +133,7 @@ ArgParser argParser = ArgParser(allowTrailingOptions: true)
   ..addFlag('track-widget-creation',
       help: 'Run a kernel transformer to track creation locations for widgets.',
       defaultsTo: false)
-  ..addFlag('gen-bytecode', help: 'Generate bytecode', defaultsTo: null)
+  ..addFlag('gen-bytecode', help: 'Generate bytecode', defaultsTo: false)
   ..addMultiOption('bytecode-options',
       help: 'Specify options for bytecode generation:',
       valueHelp: 'opt1,opt2,...',
@@ -380,7 +380,7 @@ class FrontendCompiler implements CompilerInterface {
       }
     }
 
-    compilerOptions.bytecode = options['gen-bytecode'] ?? options['aot'];
+    compilerOptions.bytecode = options['gen-bytecode'];
     final BytecodeOptions bytecodeOptions = BytecodeOptions(
       enableAsserts: options['enable-asserts'],
       emitSourceFiles: options['embed-source-text'],

pkg/vm/lib/kernel_front_end.dart

@@ -106,7 +106,7 @@ void declareCompilerOptions(ArgParser args) {
       help:
           'Split resulting kernel file into multiple files (one per package).',
       defaultsTo: false);
-  args.addFlag('gen-bytecode', help: 'Generate bytecode', defaultsTo: null);
+  args.addFlag('gen-bytecode', help: 'Generate bytecode', defaultsTo: false);
   args.addMultiOption('bytecode-options',
       help: 'Specify options for bytecode generation:',
       valueHelp: 'opt1,opt2,...',
@@ -157,7 +157,7 @@ Future<int> runCompiler(ArgResults options, String usage) async {
   final bool tfa = options['tfa'];
   final bool linkPlatform = options['link-platform'];
   final bool embedSources = options['embed-sources'];
-  final bool genBytecode = options['gen-bytecode'] ?? aot;
+  final bool genBytecode = options['gen-bytecode'];
   final bool dropAST = options['drop-ast'];
   final bool enableAsserts = options['enable-asserts'];
   final bool useProtobufTreeShaker = options['protobuf-tree-shaker'];