how to disable the run result for test complete?

Go into the options/settings panel.

There are options in there to stop it displaying the result automatically on completion and also to reduce the number of historic results stored.

Standard stuff .... https://support.smartbear.com/testcomplete/docs/testing-with/log/window/options.html

If you set Log.Enabled = false then there will not be any posted into the Test log.

Once you set the Log.Enabled = true then all logs will posted in the Test log.

Example:

Log.Enabled = false

if(Object.Exists) 
{
      Object.Keys("Test");
}

Log.Enabled = true

Log.Message("Passed")

For more details on this you can refer here