Fixes the last bits of #5759.

This reverts commit 57b4a525.

Fixes https://github.com/flutter/flutter/issues/13972

* Pin url_launcher to 1.0.3

* Commit results of 'bin/flutter update-packages --force-upgrade'

* Added TODO

* Explicitly report CFE output(when using --preview-dart-2)

* Fix test so it looks at errorText

* Fix expected text

Unsubscribe should remove RouteAware for all routes.

* Revert "Revert "Revert "Revert "Update Android sdkmanager for all platforms (#13912)" (#13922)" (#13923)" (#13935)"

This reverts commit f6fae1ce.

In this attempt we try to use SDK's with pre-accepted licenses.

* use SDK with pre-accepted licenses

* update readme

Fixes https://github.com/flutter/flutter/issues/11993

* it's fixed

* Add test for simulator log reader

Revert "Revert "Revert "Update Android sdkmanager for all platforms (#13912)" (#13922)" (#13923)" (#13935)

This reverts commit ad898ad0.

Back to the whiteboard w.r.t. Android SDK licenses.

* First version

* Prevent modification of .flutter during analytics test

* Pass in directory and override analyzer warning due to conditional import

* Review comments

This reverts commit 45289c08.

* image links

* image links with markdown formatting

changes of pull request [#13824](https://github.com/flutter/flutter/pull/13824)

* Remove empty lines

This reverts commit 65dcb3ab.

The Mac infra bot fails unable to run `android update sdk`

* Update Android sdkmanager for all platforms

* update readme

which rolls Dart to the latest version.

- includes Roll Dart to version 8d7219a5b6a7c2505ff57f23e7cf80da4c724512 (https://github.com/flutter/engine/commit/43327730a27344f1d45a1f9e4d53b14260778ce5)

includes the following CLs since the last roll
- Further improve painting.dart documentation. (#4505)
- Add support for --strong option in the engine, create a strong mode
  version of platform file (#4504)
- Apply texture transform on Android (#4513)
- [fuchsia] Removed the flutter_app template. (#4511)
- This adds RPC call to set asset path. (#4323)
- Fix windows build by using lambda capture workaround (#4514)
- Add missing include for sk_malloc_throw

This broke the coverage tool, as material/animated_icons/animated_icons.dart
was loaded twice as a part, once directly animated_icons_private_test, and one
through animated_icons_private_test->flutter_tester->...->material

The coverage package assumes a 1:1 mapping between VM scripts and URIs due to a
limitation in the underlying vm_service_client package, which currently doesn't
provide a unique identifier for VM scripts.

The underlying issue is tracked by dart-lang/coverage#194.

* Send RPC request to switch assets directory on hot reload.

This is needed to pick up updated assets that are expected to be picked up on hot reload.

* Assert assets directory is not null.

* Better multiple future wait

* Add type annotation

* updated docs to remove note about windows tests not working

* reverted formatting