RFR(XS): 8193237 - SA: ClhsdbLauncher should show the command being executed

[Chris Plummer]

Hello,

Please review the following:

https://bugs.openjdk.java.net/browse/JDK-8193237
http://cr.openjdk.java.net/~cjplummer/8193237/webrev.00/

The fix is to issue an "echo on" command before the test commands. The 
bug gives an example of how this fix improves the test output.

thanks,

Chris