RFR: JDK-8238692: MacOS runtime Installer issue

Please review the jpackage fix at [1] for the related issues [2], [3], and [4]. This will basically make pkg type runtime installers work on macosx, while we wait for JDK-8237971 to either fix or disable dmg type runtime installers. /Andy [1] http://cr.openjdk.java.net/~herrick/8238692/webrev.02/ [2] https://bugs.openjdk.java.net/browse/JDK-8238692 [3] https://bugs.openjdk.java.net/browse/JDK-8237966 [4] https://bugs.openjdk.java.net/browse/JDK-8237970