RFR: 8248905: [macos] symbolic links not properly resolved

[alexander.matveev at oracle.com]

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

- Fixed by converting path of executable to real path if 
_NSGetExecutablePath() returned symbolic link.

[1] https://bugs.openjdk.java.net/browse/JDK-8248905
[2] http://cr.openjdk.java.net/~almatvee/8248905/webrev.00/

Thanks,
Alexander