Manual roll is needed because incoming dart sdk requires updated version
vm_snapshot_analysis (>=0.7.4).


https://github.com/flutter/engine/compare/5ae09b8b4fa381e8723ed5382a26eafd0d97236f...7c83ea3e854202aea22405a947ac1b8f18c5a72c

```
7c83ea3e85 Reland "Manual roll Dart SDK from 2d98d9e27dae to 0b07debd5862 (21 revisions) (#43457)" (#43472)
9ef3e8d533 Roll Skia from 5eba922297bb to 93c92f97f5ab (2 revisions) (#43471)
```

Remove implementation of SuitePlatform from the test as well. Remove use
of fake cwd from SuitePlatform as it can't be properly faked.

When building the new SDK DAPs, this functionality was missed from the Flutter adapter (but added to the Dart CLI adapter).

As well as passing a VM Service URI directly, we support passing a file that can be polled for it.

This uses the same mechanism we use to obtain the VM Service URI from a Dart debug session (we run `dart --write-service-info=foo.json my_file.dart` and then poll that file which the VM will write) and is useful for users that have their own mechanism for launching an app (for example using custom Flutter embedders - see https://github.com/Dart-Code/Dart-Code/issues/3353) to provide a VM Service URI once the app is up and running.

Fixes https://github.com/Dart-Code/Dart-Code/issues/4577.

The editor is set to hot-reload-on-save by default so saving while the debug session is starting currently prints an error:

Failed to Hot Reload: app 'null' not found

![image](https://github.com/flutter/flutter/assets/1078012/a125b455-a46d-4993-98d8-5d8ae7237a00)

This change skips the call to `app.restart` if the app hasn't started yet to avoid printing an error.

[flutter_tools/dap] Inform DAP client whether restart is supported

Fixes https://github.com/Dart-Code/Dart-Code/issues/4293.

* [flutter_tools] Forward app.webLaunchUrl event from Flutter to DAP clients

Fixes https://github.com/Dart-Code/Dart-Code/issues/4292.

* Update packages/flutter_tools/lib/src/debug_adapters/flutter_adapter.dart
Co-authored-by: Christopher Fujino <fujino@google.com>

* Another static const instead of final
Co-authored-by: Christopher Fujino <fujino@google.com>

[flutter_tools/dap] Add support for forwarding `flutter run --machine` exposeUrl requests to the DAP client (#114539)

* [flutter_tools/dap] Add support for forwarding `flutter run --machine` requests to the DAP client

Currently the only request that Flutter sends to the client is `app.exposeUrl` though most of this code is generic to support other requests that may be added in future.

* Improve comment

* Fix thrown strings

* StateError -> DebugAdapterException

* Add a non-null assertion and assert

* Use DebugAdapterException to handle restartRequests sent before process starts

* Fix typo + use local var

* Don't try to actually send Flutter messages in tests because there's no process

[flutter_tools/dap] Map org-dartlang-sdk URIs to the location of the source files found by the analyzer (#114369)

[dap] Don't wait for appStarted before responding to launch/attach + don't call app.stop for unstarted app (#109386)

* [flutter_tools] [dap] Ensure DAP sends app.stop/app.detach during terminate

Fixes an issue where the flutter_tester device may not be cleaned up correctly if we just terminate the Flutter process.

* Update integration test expectations

* Revert accidental commit

* [flutter_tools] [dap] Add support for passing env variables to spawned processes

* Use named args

* Use in-memory fs and FakePlatform

* Pass filesystem style to MemoryFileSystem

* Don't terminate Dart process pids from VM Service

These processes may be on another device, and in the case of attach the debugee should not be terminated anyway.