[Investigation] Allow to use JDK 9 and later

[suhtai]

I'm not entirely sure of what is required but limiting the JDK to 9 may come with problems in the near future. Jetpack Compose and AGP 7.0.0 require JDK 11, so it's not possible to have a project using Compose at the same time as this project on the same IDE.

[rachelcarmena]

I think it would be necessary to differentiate:

• The requirements to build Arrow to be able to contribute with its development
• The requirements to use Arrow

There was an interesting chat about it in KotlinLang Slack about it.

[suhtai]

From the looks of it this seems to be that we require to add toolJar as a dependency for compiling the tests source code. On SDK 11 running ./gradlew build runs OK, so I think that it should be enough to not include the toolJar if it's not there. I'll open a PR to test this 🤞