Doclets do not work with JDK11

It's not able to build Infinispan with JDK 11.

Module infinispan-commons contains JDK specific classes which requires to be built in JDK 9+ (JDK 11 is LTS) but it's not able to build the whole Infinispan project with distribution profile related to fails on missing classes for infinispan-doclets module (referencing com.sun.javadoc*) using tools.jar which are not the part of JDK 9+ anymore. The failure is also on generating javadoc for infinispan-commons which uses sun.reflect.Reflection.getCallerClass which is discontinuing in JDK 11.