Java 16

Pattern matching for instanceof cleanup has been coded for Java 15
preview feature and now should be coded for Java 16+

It requires to:
 - Change the Java version check
 - Move the unit tests
 - Update the wordings

Change-Id: Icf6de856b8a5d87309628aa3b243f285852dd1e2
Signed-off-by: Fabrice Tiercelin <fabrice.tiercelin@yahoo.fr>