* Reland 9534082fc0 with fix for incremental compilation.
When in incremental mode, awaiting exitCode won't work because compiler is not expected to exit after compilation.
Instead listen for stdout stream closing and report error if outputFilename has not been received.
* Fix lints
* 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.
