[jnigen] Parse Kotlin's metadata + Remove `suspend_fun_to_async` flag in config (https://github.com/dart-lang/jnigen/issues/308)

* Parse Kotlin's metadata in API Summarizer
* Remove `suspend_fun_to_async` from config now that `isSuspend` reliably detect `suspend fun`s.
24 files changed
tree: 2d6c938360939e387a2cad32430f3e2920f30af4
  1. .github/
  2. pkgs/