RFR: 8168414 Various timeouthandler fixes

[Staffan Larsen]

When looking for some timeout handler problems I found a few things that should be fixed: 

* Strange use of Thread.currentThread().interrupt() 
* Add logging for timeouts 
* Milliseconds sometimes printed as microseconds or nanoseconds 
* Should use destroyForcibly() to terminate processes 
* No need to sleep in the last iteration when running a command multiple times 
* Disable timeout handling timeouts since we do that ourselves 

I didn’t want to file individual bugs for all of these, so I have lumped them together in one bug.

bug: https://bugs.openjdk.java.net/browse/JDK-8168414 <https://bugs.openjdk.java.net/browse/JDK-8168414>webrev: http://cr.openjdk.java.net/~sla/8168414/webrev.00 <http://cr.openjdk.java.net/~sla/8168414/webrev.00>

Thanks,
/Staffan