Add search functionality for component that shows test logs

Javatest 4.2 (actual for previous versions as well).

There is no "search" functionality in the component that shows test logs in the "Test Run Messages" tab of the Harness. Sometimes, logs can be quite large and it would be nice to have ability to search them. This can be implemented similarily to "quick search" functionality of the Log Viewer window.

This request can be generalized as "Add search functionality for all Harness windows where applicable": Tree of Tests, Documentation, Files (source code), Logs, etc. etc.