Jetty 12.0.x xmlconfig prefers interfaces

[janbartel]

Fixes #11895.

Tentative fix to improve ordering of method matches so that:

• methods with fewer args are preferred
• methods with primitive args are preferred
• methods with non-varargs are preferred
• methods with class args (that are not the Object.class) are preferred
• methods with interface args or class args preference the most derived type

[joakime]

@janbartel rebase against jetty-12.1.x

[gregw]

I think this is a good change for 12.1, I'm not so worried by this now (cue disaster!)

[gregw]

@janbartel can you rebase this to 12.1, I think it is a good change to make.

[janbartel]

Rebase done.

[gregw]

LGTM