[FIXED JENKINS-21386] Allow reordering loggers, use first with matching ...

...name.

This change uses the top-most matching log recorder (based on name) to determine whether a log message should be added.

If both `com` (at `INFO`) and `com.example` (at `WARNING`) are defined for a specific log recorder, a log message in logger `com.example.Foo` will only be logged if it's `WARNING` or `SEVERE`, or the `com` logger is above the `com.example` logger in the loggers list.

This change will definitely impact existing configurations that start out with fairly restrictive log levels on e.g. `com`, to be more verbose with specific loggers later.

This PR is one of two proposed solutions to [JENKINS-21386](https://issues.jenkins-ci.org/browse/JENKINS-21386), the other being #1090.