Eliminate MacOSX install build dependency on native2ascii

JDK-8074431 proposes to remove native2ascii in JDK 9. MacOSX installer currently has a dependency on native2ascii tool to convert localized JDK.properties and JRE.properties files to UTF-8 such that the strings are used in generating Welcome.html and Conclusion.html. Such build dependency on native2ascii is not strictly necessary and should be eliminated.

Michael Fang from Globalization Engineering (coordinating translation process with WPTG) suggests to use either .strings file or .wxl that will be delivered from WPTG in UTF-8. In the translation build system, .properties file is designed to be delivered back in ASCII. In the same token, .strings/.wxl files are designed to be delivered back in UTF-8 from the translation factory.
 
Another option is to include the native2ascii source as the install build tool.