VersionProps duplicate and skipped initialization

VersionProps.java.template has a static initializer that calls init().
The init method is also called from System.java which has the effect of init being called twice.

The "java.version" property is set twice/thrice, once in the native code (System.c) and again by the VersionProps.init() method.

Added tests also exposed a bug in which calling System.setProperties(null) did not initialize the version properties.