Repository: flutter
Issue: [Test]: Golden Test Fails on CI(Same Platform)
Labels: a: tests,framework,platform-mac,P3,a: gamedev,customer: chilli,team-framework,triaged-framework

## Steps to Reproduce

<!-- You must include full steps to reproduce so that we can reproduce the problem. -->

1. Run ``` flutter test --update-goldens``` on local machine 
2. Run ```flutter test``` on CI machine

**Expected results:** <!-- what did you want to see? -->
Test should pass

**Actual results:** <!-- what did you see? -->
Test fails 

IsolatedDiff
![welcome_isolatedDiff](https://user-images.githubusercontent.com/3314171/81099428-32ec9880-8f0b-11ea-8f14-33885aa38c56.png)

<details>
  <summary>Logs</summary>

```
The following TestFailure object was thrown running a test:
  Expected: one widget whose rasterized image matches golden image "goldens/welcome.png"
  Actual: _WidgetTypeFinder:<exactly one widget with type "LocalizedLytApp" (ignoring offstage
widgets): LocalizedLytApp>
   Which: Golden "goldens/welcome.png": Pixel test failed, 0.32% diff detected.
          Failure feedback can be found at /Users/jenkins/vstsagent/_work/3/s/test/failures

When the exception was thrown, this was the stack:
#0      fail (package:test_api/src/frontend/expect.dart:154:30)
#1      _expect.<anonymous closure> (package:test_api/src/frontend/expect.dart:128:9)
#13     MatchesGoldenFile.matchAsync.<anonymous closure> (package:flutter_test/src/_matchers_io.dart)
<asynchronous suspension>
#14     MatchesGoldenFile.matchAsync.<anonymous closure> (package:flutter_test/src/_matchers_io.dart)
#15     AutomatedTestWidgetsFlutterBinding.runAsync.<anonymous closure> (package:flutter_test/src/binding.dart:921:22)
#18     AutomatedTestWidgetsFlutterBinding.runAsync (package:flutter_test/src/binding.dart:919:26)
#19     MatchesGoldenFile.matchAsync (package:flutter_test/src/_matchers_io.dart:72:20)
#20     _expect (package:test_api/src/frontend/expect.dart:117:26)
#21     expectLater (package:test_api/src/frontend/expect.dart:76:5)
#22     expectLater (package:flutter_test/src/widget_tester.dart:406:10)
#23     main.<anonymous closure>.<anonymous closure>.<anonymous closure> (file:///Users/jenkins/vstsagent/_work/3/s/test/widget_test.dart:43:15)
#34     FakeAsync.flushMicrotasks (package:fake_async/fake_async.dart:192:32)
#35     AutomatedTestWidgetsFlutterBinding.runTest.<anonymous closure> (package:flutter_test/src/binding.dart:1102:19)
(elided 35 frames from dart:async, dart:async-patch, and package:stack_trace)
```


flutter doctor -v on CI machine 
```
[✓] Flutter (Channel master, 1.18.0-9.0.pre.123, on Mac OS X 10.15.4 19E287, locale en-DK)
    • Flutter version 1.18.0-9.0.pre.123 at /Users/jenkins/vstsagent/_work/3/flutter
    • Framework revision a48a51b0ff (56 minutes ago), 2020-05-05 09:54:21 -0700
    • Engine revision 494a63c411
    • Dart version 2.9.0 (build 2.9.0-3.0.dev cab69e7706)

 
[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
    • Android SDK at /Users/jenkins/Library/Android/sdk
    • Platform android-29, build-tools 28.0.3
    • ANDROID_HOME = /Users/jenkins/Library/Android/sdk
    • Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b49-5587405)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.4.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.4.1, Build version 11E503a
    • CocoaPods version 1.9.1

[!] Android Studio (version 3.5)
    • Android Studio at /Applications/Android Studio.app/Contents
    ✗ Flutter plugin not installed; this adds Flutter specific functionality.
    ✗ Dart plugin not installed; this adds Dart specific functionality.
    • Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b49-5587405)

[✓] VS Code (version 1.41.1)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.8.1

[!] Connected device
    ! No devices available

! Doctor found issues in 2 categories.
```

flutter doctor -v on local machine 
```
[✓] Flutter (Channel master, 1.18.0-9.0.pre.122, on Mac OS X 10.15.4 19E287,
    locale en-DK)
    • Flutter version 1.18.0-9.0.pre.122 at /Users/b044560/Development/flutter
    • Framework revision 9a99403ad2 (15 hours ago), 2020-05-04 22:29:02 -0400
    • Engine revision 95ecd9a405
    • Dart version 2.9.0 (build 2.9.0-5.0.dev e7bebea059)

 
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
    • Android SDK at /Users/b044560/Library/Android/sdk
    • Platform android-29, build-tools 29.0.2
    • ANDROID_HOME = /Users/b044560/Library/Android/sdk
    • Java binary at: /Applications/Android
      Studio.app/Contents/jre/jdk/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build
      1.8.0_202-release-1483-b49-5587405)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS (Xcode 11.4.1)
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 11.4.1, Build version 11E503a
    • CocoaPods version 1.9.1

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 3.5)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin version 44.0.1
    • Dart plugin version 191.8593
    • Java version OpenJDK Runtime Environment (build
      1.8.0_202-release-1483-b49-5587405)

[✓] VS Code (version 1.44.2)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.10.1

[✓] Connected device (3 available)
    • Nota’s iPhone  • 00008030-001470DE010A802E • ios            • iOS 13.3.1
    • Web Server     • web-server                • web-javascript • Flutter
      Tools
    • Chrome         • chrome                    • web-javascript • Google
      Chrome 81.0.4044.129

• No issues found!
```

</details>