Breaking change introduced in SpanData, ReadableSpan interfaces

[jkwatson]

This PR: #4256 Introduced new methods to public interfaces without providing default implementations. This is a breaking change, and hence a bug. We need to add default implementations ASAP and issue a patch release to correct this.

[jack-berg]

I see additional methods without default implementation added to ReadableSpan and SpanData.

There's also an abstract method added to the autovalue builder TestSpanData.Builder#setInstrumentationScopeInfo, but I believe we don't have to add a default implementation because the builder already has package private methods that prevents users from implementing their own.

That was first published in 1.13.0. Thoughts on patching back to 1.13.0, or just the latest 1.16.0?

[jkwatson]

The user who reported this says they were able to workaround, so perhaps we can put off releasing a patch until we have a user who needs it. We should still add the default methods, I think, so it isn't a problem moving forward.