RFR: JDK-8249289: Exception thrown when --temp points to non-existant directory

[Andy Herrick]

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

This fixes the regression in JDK16 which caused exception when an empty 
directory was used int the --temp jpackage option, and added to the 
existing test.

[1] - https://bugs.openjdk.java.net/browse/JDK-8249289

[2[ - http://cr.openjdk.java.net/~herrick/8249289/webrev.02/

/Andy