Fix dart run test -p chrome -c dart2wasm (#2233)

* Fix `dart run test -p chrome -c dart2wasm`

package:test should not depend and use Dart SDK internal files, flags or
other internal things for invoking compilers.

Instead it should use the public `dart compile wasm` command.

Closes #2210

* fix testing to do last supported and dev

Author: mkustermann

.github/workflows/dart.yml

@@ -1,7 +1,8 @@
 # See https://pub.dev/packages/mono_repo
 
 sdk:
-- main
+- pubspec
+- dev
 
 stages:
 - analyze_and_format: