New port: java/jattach

The utility to send commands to remote JVM via Dynamic Attach mechanism.
All-in-one jmap + jstack + jcmd + jinfo functionality in a single tiny program.
No installed JDK required, works with just JRE.

This is the lightweight native version of HotSpot Attach API
https://docs.oracle.com/javase/8/docs/jdk/api/attach/spec/

WWW: https://github.com/apangin/jattach

PR: 222660
Submitted by: Michael Zhilin <mizhka@gmail.com>