[jnigen] Override JObject's toString with appropriate Java's toString (https://github.com/dart-lang/jnigen/issues/337)

* add toString
* remove extra hashCode and == as JObject already has it
4 files changed
tree: 07ebef58e1d9e071ef8cdeb8885d9ebef01b8727
  1. .github/
  2. pkgs/