[ML] Info and debug level log throttling

#1615 introduces per log line rate based throttling of warn and error messages. We also have some message deduplication on the Java side: repeated lines are deduplicated. It is easier to reason about logging if all throttling occurs in one place. We also currently pay the price of writing the message over the named pipe to Java before deduplicating.

We should move debug and info level log throttling to C++ and remove the Java throttling we currently have. We should also decide whether we want to retain the old mechanism of only retaining the last line, move to per log line based throttling as we have for warn and error or not throttle at all for info and debug logging.