Cleanup obsolete --compact-async compiler option (#118894)

packages/flutter_tools/lib/src/compile.dart

@@ -21,8 +21,6 @@ import 'convert.dart';
 
 /// Opt-in changes to the dart compilers.
 const List<String> kDartCompilerExperiments = <String>[
-  // improve AOT code size.
-  '--compact-async',
 ];
 
 /// The target model describes the set of core libraries that are available within

packages/flutter_tools/test/general.shard/compile_batch_test.dart

@@ -200,7 +200,6 @@ void main() {
           '--no-print-incremental-dependencies',
           '-Ddart.vm.profile=true',
           '-Ddart.vm.product=false',
-          '--compact-async',
           '--no-link-platform',
           '--aot',
           '--tfa',
@@ -249,7 +248,6 @@ void main() {
           '--no-print-incremental-dependencies',
           '-Ddart.vm.profile=false',
           '-Ddart.vm.product=true',
-          '--compact-async',
           '--no-link-platform',
           '--aot',
           '--tfa',

packages/flutter_tools/test/general.shard/compile_test.dart

@@ -105,13 +105,11 @@ void main() {
   testWithoutContext('buildModeOptions removes matching profile define in profile mode', () {
     expect(buildModeOptions(BuildMode.profile, <String>['dart.vm.profile=true']), <String>[
       '-Ddart.vm.product=false',
-      '--compact-async'
     ]);
   });
 
   testWithoutContext('buildModeOptions removes both matching profile and release define in profile mode', () {
     expect(buildModeOptions(BuildMode.profile, <String>['dart.vm.profile=false', 'dart.vm.product=true']), <String>[
-      '--compact-async'
     ]);
   });
 }