After one year of no releases, things are really moving in PowerMock.
PowerMock 2.0.0-RC1 was released. And with PowerMockito 2.0.0-RC1
+ @PowerMockIgnore({"com.sun.org.apache.xerces.*", "javax.xml.*", "org.xml.*", "org.w3c.*"})
The tests work under Java 11.