Enable JVM Unit Tests for Gradle

Summary:
This makes sure all the tests are executed inside the `ReactAndroid/src/test` folder.
Currently, we're not executing those tests as they're broken. In this diff I took care of:
- Re-enabling them as much as I could
- Ignoring the ones that are ignored also on BUCK

Those tests will have to be entirely re-written as they're using PowerMock which is
unmaintained and not working well with JDK 17+ (that's also why I had to add
the `--illegal-access=permit` and the `--add-opens` directing to allow mocking).

In general, I believe this is a net positive change as it allows us to add new JUnit tests
that are effectively executed, while the current status is ignoring all of them.

Changelog:
[Internal] [Changed] - Enable JVM Unit Tests for Gradle

Reviewed By: cipolleschi

Differential Revision: D41523697

fbshipit-source-id: dc9f2c4c93d0e6b231e8240a583ca31220152d3f