* Plumb a --strong option through to the front end server and the engine
so that we can run flutter apps in preview-dart-2 and strong mode
* - Address analyzer lint issues
*- correctly set up strong mode option in the case of AOT builds
* Fix restart flow for preview-dart-2 mode.
Restart in preview-dart-2 needs to use kernel file and it has to be complete, rather than incremental kernel file.
* Add curly braces
* Do full compile on restart
* Roll engine to pick up changes to hot reload for preview-dart-2
This CL introduces 2 hidden options to 'flutter build aot' and 'flutter run' for passing arbitrary arguments to front-end server and to gen_snapshot tool when building and running flutter app in --profile or --release modes.
The ability to pass arbitrary options simplifies various experiments, as it removes the need to change defaults and rebuild flutter engine for every tested configuration.
