preserve sun.misc.Launcher.getLauncher in openjdk.pro

The VM calls this method when booting, so we need to tell ProGuard to
retain it.

openjdk.pro

@@ -14,6 +14,10 @@
    public static void setProperties(java.util.Properties);
  }
 
+-keep class sun.misc.Launcher {
+   public static sun.misc.Launcher getLauncher();
+ }
+
 -keep class java.lang.ClassLoader {
    private static java.lang.ClassLoader scl;
    private static boolean sclSet;
@@ -281,4 +285,4 @@
 -keepclassmembers class java.util.concurrent.SynchronousQueue$TransferStack$SNode {
 	*** match;
 	*** next;
-}
+}