Consider using Multi-Release jars for Error Prone

This bug tracks trying to use [Multi-Release jar files](https://openjdk.org/jeps/238) for Error Prone.

The main use-case is that some checks need to handle AST nodes that not available in all supported JDK versions. Currently we're mostly using reflection to work around that, with mrjars we could move some of that logic behind an internal API and provide implementations that used the new AST nodes for JDK versions that supported them, avoiding the reflection. (e.g. #3737, https://github.com/google/error-prone/pull/3610#discussion_r1051486417)

One of the barriers to doing this is figuring out the best way to produce mrjars with maven. (If anyone reading this has relevant experience, suggestions are welcome!)