Partial support for --ts-flat-files and --gen-all (#7446)

* Partial support for --ts-flat-files and --gen-all

* Add generated code changes

* remove some debugging code left over

* missed grpc files

tests/monster_test_generated.ts

@@ -1,3 +1,5 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
 export { Monster } from './my-game/example/monster';
 export { Monster as MyGameExample2Monster, MonsterT as MyGameExample2MonsterT } from './my-game/example2/monster';
 export { Ability, AbilityT } from './my-game/example/ability';