Ydoc server logging works the same as any other logging

[JaroslavTulach]

This issue is related to:

• Use -p mode only when building ydoc-server native image #14878
• Replace language server WebSocket connection with Ydoc #14438
• and previous work done by Logging from the other JVM delegates to the primary JVM #14788

While the work on #14788 introduce extensive test suites, those tests are creating logger on a fly - however ydoc-server project is native image compiled with class static initializers executed at build time. As such a classical code:

private static final Logger LOG = Logger(Factory).getLogger(...)

is hardwired during compilation. Currently it gets on hold of a wrong logger. This needs to get fixed. When at it fix also the documentation.

[JaroslavTulach]

• demo showing how to get System.Logger working in NI
• substituations to reset LoggerFinder fields in the JDK
• feature to replace all already created System.Logger instances with a proxy

[JaroslavTulach]

• related System.Logger.isLoggable returns true for any level #14948