Added and example to the ListView docs that shows how to have a custom UI for an empty list.

Fixes #55765

We are currently only returning the first device from dev-finder, instead we need to look at the whole list.

Fixes #56194

Remove caching of FlutterView and poll forever if the list of flutter views is empty. Added test for missing release mode logic.

This reverts commit 209bdcb6.

this is being done to revert the previous comment which was a trial
version of the engine that has a NNBD enabled Dart sdk.

Remove caching of FlutterView. Perhaps the FlutterView RPC might return an empty list if the VM is not quite up yet? We had some old logic to poll the flutter views RPC for up to 200ms. That doesn't seem like a great approach, so instead we could forgo it entirely and trust that either the views come up before the developer tries to interact, or we crash.

* Trial PR to use an engine that has the null safety unfork CL in it.

* Fix mack specification for test.

* enable macOS desktop

* enable all configs on CI

* Update track_widget_creation_enabled_task.dart

* Update framework.dart

* remove FLUTTER_WEB

* remove config environment variables

* configure in correct spot

This is required to run the macOS twc enabled devicelab test.

Ensure --no-track-widget-creation is piped through android/macOS. Adds integration testing for iOS/android/macOS

An upcoming Dart SDK change
(https://github.com/dart-lang/sdk/commit/fa2fd41166db35afa4777e63f900e83d25709c5c)
changes the precise text of the exception generated by `utf8.decode`
if a non-UTF8 file is found.  This is causing a breakage in the Dart
team's `flutter-analyze` bot (and will presumably cause a breakage in
the corresponding Flutter bot as soon as this change is rolled into
Flutter).  To avoid this breakage, the bot shouldn't rely on the exact
exception text; it is sufficient to simply catch a FormatException.

2037e0f18 Roll src/third_party/dart c3ce87355614..d5af40b640f7 (1 commits) (flutter/engine#18110) (#56258)

Redirects stdout/stderr in the Windows template when creating a console. This fixes the console opened when running from Visual Studio to actually show output, instead of being empty.

Fixes #53169

7a492012a Roll src/third_party/skia 80cab814091d..57f289d7423c (1 commits) (flutter/engine#18105) (#56233)

813fd04c7 Roll src/third_party/dart a42e6ac0356d..c3ce87355614 (3 commits) (flutter/engine#18103) (#56225)

94e6baa75 Roll src/third_party/dart be1f85847fd5..a42e6ac0356d (1 commits) (flutter/engine#18102) (#56215)