Remove interchange logging for sections where nothing happens (#3842)

The interchange tight loops through several sections. Two of those
sections log that they are doing nothing. Other sections only log when
they do something.

This PR makes those two sections no longer log when they do nothing.

As an example, an interchange idle for 20 seconds in a test case on my
laptop logs:

before this PR: 5699 lines
after this PR: 1925 lines

The bulk of the remaining 1925 lines is another per-iteration message
that is interchange status summary information, rather than per-section
activity logging. Rather than implement something specific for this
message to log it less frequently, this is left for a future PR which
will make the interchange loop only when something happens, rather than
in a tight poll.

# Description

Please include a summary of the change and (optionally) which issue is
fixed. Please also include
relevant motivation and context.

# Changed Behaviour

Which existing user workflows or functionality will behave differently
after this PR?

# Fixes

Fixes # (issue)

## Type of change

Choose which options apply, and delete the ones which do not apply.

- Bug fix
- New feature
- Update to human readable text: Documentation/error messages/comments
- Code maintenance/cleanup

Author: benclifford

parsl/executors/high_throughput/interchange.py

@@ -220,11 +220,11 @@ def _send_monitoring_info(self, monitoring_radio: Optional[MonitoringRadioSender
     def process_command(self, monitoring_radio: Optional[MonitoringRadioSender]) -> None:
         """ Command server to run async command to the interchange
         """
-        logger.debug("entering command_server section")
 
         reply: Any  # the type of reply depends on the command_req received (aka this needs dependent types...)
 
         if self.command_channel in self.socks and self.socks[self.command_channel] == zmq.POLLIN:
+            logger.debug("entering command_server section")
 
             command_req = self.command_channel.recv_pyobj()
             logger.debug("Received command request: {}".format(command_req))
@@ -492,8 +492,6 @@ def process_tasks_to_send(self, interesting_managers: Set[bytes], monitoring_rad
                 else:
                     interesting_managers.remove(manager_id)
             logger.debug("leaving _ready_managers section, with %s managers still interesting", len(interesting_managers))
-        else:
-            logger.debug("either no interesting managers or no tasks, so skipping manager pass")
 
     def process_results_incoming(self, interesting_managers: Set[bytes], monitoring_radio: Optional[MonitoringRadioSender]) -> None:
         # Receive any results and forward to client