Add timestamps to jpackage and jpackage tests verbose output

We need to add timestamps to jpackage and jpackage tests verbose output, so we can determine how long each command is executed. We have several tests timeout and it seems due to that some external commands jpackage runs takes a lot of time. Unfortunately we do not have timestamps in our verbose output to determine which command took most time, so we need to improve our verbose output to include timestamps.

See JDK-8248248 for test example which failed due to timeout, but it is hard to tell what exactly took time.