Repository: flutter
Issue: flutter build ios - Crash  - [tool_crash] FormatException : Missing extension byte (at offset 17)
Labels: c: crash,platform-ios,tool,a: build,P2,team-ios,triaged-ios

## Command
```
flutter build ios
```

## Steps to Reproduce
1. ...
2. ...
3. ...

## Logs
FormatException
```
#0      _Utf8Decoder.convertChunked (dart:convert-patch/convert_patch.dart:1892:7)
#1      _Utf8ConversionSink.addSlice (dart:convert/string_conversion.dart:314:28)
#2      _Utf8ConversionSink.add (dart:convert/string_conversion.dart:310:5)
#3      _ConverterStreamEventSink.add (dart:convert/chunked_conversion.dart:72:18)
#4      _SinkTransformerStreamSubscription._handleData (dart:async/stream_transformers.dart:111:24)
#5      _rootRunUnary (dart:async/zone.dart:1436:47)
#6      _CustomZone.runUnary (dart:async/zone.dart:1335:19)
#7      _CustomZone.runUnaryGuarded (dart:async/zone.dart:1244:7)
#8      _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
#9      _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#10     _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:733:19)
#11     _StreamController._add (dart:async/stream_controller.dart:607:7)
#12     _StreamController.add (dart:async/stream_controller.dart:554:5)
#13     _Socket._onData (dart:io-patch/socket_patch.dart:2160:41)
#14     _rootRunUnary (dart:async/zone.dart:1444:13)
#15     _CustomZone.runUnary (dart:async/zone.dart:1335:19)
#16     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1244:7)
#17     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:341:11)
#18     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
#19     _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:733:19)
#20     _StreamController._add (dart:async/stream_controller.dart:607:7)
#21     _StreamController.add (dart:async/stream_controller.dart:554:5)
#22     new _RawSocket.<anonymous closure> (dart:io-patch/socket_patch.dart:1696:33)
#23     _NativeSocket.issueReadEvent.issue (dart:io-patch/socket_patch.dart:1208:14)
#24     _microtaskLoop (dart:async/schedule_microtask.dart:40:21)
```
```
[✓] Flutter (Channel master, 2.3.0-1.0.pre.205, on macOS 11.1 20C69 darwin-x64, locale en)
    • Flutter version 2.3.0-1.0.pre.205 at /Users/bestcomp/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 96e4b47f5d (17 hours ago), 2021-05-02 07:24:01 -0700
    • Engine revision 3e578c6e0d
    • Dart version 2.14.0 (build 2.14.0-48.0.dev)

[✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3)
    • Android SDK at /Users/bestcomp/Library/Android/sdk
    • Platform android-30, build-tools 30.0.3
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 12.4, Build version 12D4e
    • CocoaPods version 1.10.1

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 4.1)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 1.8.0_242-release-1644-b3-6915495)

[✓] VS Code (version 1.40.2)
    • VS Code at /Users/bestcomp/Downloads/Visual Studio Code.app/Contents
    • Flutter extension version 3.8.1

[✓] Connected device (1 available)
    • Chrome (web) • chrome • web-javascript • Google Chrome 90.0.4430.93

• No issues found!

```

## Flutter Application Metadata
**Type**: app
**Version**: 4.0.1+11
**Material**: true
**Android X**: false
**Module**: false
**Plugin**: false
**Android package**: null
**iOS bundle identifier**: null
**Creation channel**: stable
**Creation framework version**: 8874f21e79d7ec66d0457c7ab338348e31b17f1d
### Plugins
connectivity-2.0.2
connectivity_for_web-0.3.1+4
connectivity_macos-0.1.0+7
file_picker-2.1.7
flutter_full_pdf_viewer-1.0.6
flutter_plugin_android_lifecycle-1.0.11
flutter_secure_storage-3.3.5
image_picker-0.6.7+22
import_js_library-1.0.2
libphonenumber-1.0.2
onesignal_flutter-2.6.3
open_file-3.1.0
path_provider-1.6.28
path_provider_linux-0.0.1+2
path_provider_macos-0.0.4+8
path_provider_windows-0.0.5
permission_handler-5.1.0+2
shared_preferences-0.5.12+4
shared_preferences_linux-0.0.2+4
shared_preferences_macos-0.0.1+11
shared_preferences_web-0.1.2+7
shared_preferences_windows-0.0.2+3
sqflite-2.0.0+3
url_launcher-5.7.10
url_launcher_linux-0.0.1+4
url_launcher_macos-0.0.1+9
url_launcher_web-0.1.5+3
url_launcher_windows-0.0.1+3
video_player-1.0.1
video_player_web-0.1.4+1
wakelock-0.2.1+1
wakelock_web-0.1.0+3
webview_cookie_manager-1.0.8
webview_flutter-1.0.7