RFR: JDK-8230726: Improve jpackage jtreg tests

[Alexey Semenyuk]

Please review the jpackage fix for bug [1] at [2].

This is a fix for the JDK-8200758-branch branch of the open sandbox 
repository (jpackage).

- reworked jpackage tests that produce platform specific packages to get 
rid of code duplication;
- replaced install.sh/uninstall.sh scripts on Linux and Windows with 
shared manage_packages.sh script that will batch install/uninstall 
packages. Support for dmg, pkg and exe installers TBD.

[1] https://bugs.openjdk.java.net/browse/JDK-8230726

[2] http://cr.openjdk.java.net/~asemenyuk/8230726/webrev.03

Thanks,
Alexey