Reland "AOT support for Linux Desktop I: switch Linux builds to assemble (#41612)" (#42030)" (#42038)

This reverts commit 142a8630.

This reverts commit 3024053c.

Bytecode generation will otherwise omit assert code, causing --enable-asserts to have no effect in the VM.

* Generate projects using the new Android embedding

* Add comment about usesNewEmbedding:true

* Feedback

* Rework way to detect new embedding in new apps

Revert "replace package:vm_service_client with package:vm_service in the devicelab project (#41646)" (#41960)

* Stop using build_runner for dart2js

* fixes to yield when computing hashes and to imports

* add missing await

* Update filecache_test.dart

* Fix paths in filecache test

* use file uri for import

* add test cases and configurable override

* remove test dep

* fix filepaths for windows

* test no longer failing

* fix paths for test cases

* fix typo

* address comments

* make a constant

* make filehash async and use constant

* fix silly logic error

* add missing trailing commas

* add more missing trailing commas

* add more and more missing trailing commas

This reverts commit 8e231796.

Adds macOS support for `flutter create`:
- Currently it is behind a hidden flag.
- Adds a TargetPlatform workaround to lib/main.dart in the standard app template when enabled.
- Supports `app` and `plugin`; `module` support doesn't yet exist for macOS in general.

This will eliminate the need to use FDE's examples as templates on macOS. The templates are based on the current state of FDE's examples, with templating support added (and with adoption of the new application delegate in the app, which hadn't been done yet in FDE, eliminating some boilerplate from the template).

Fixes #30703 

Moves the generated config into that directory. Matches the structure of
the other desktop projects.

Also fixes #40265