Make javax.xml.soap. dynamically accessed to work around Java 9 issues

[cowtowncoder]

Looks like Java 9 by default provides smaller set of classes, and one case where this affects Jackson directly (as per unit tests) is lack of esoteric type javax.xml.soap.Detail.
Since I can't see anything explicit under src/main I suspect it's a test artifact; nonetheless test shouldn't fail on Java 9 as it does currently: either test should dynamically see if class is available or just remove.

[cowtowncoder]

Looks like there is no explicit support for javax.xml.soap.Detail, and the origin of the broken test (TestSOAP) is bit of a mystery; further, test really does not test output wrt validity. So I think I will just go ahead and remove it so as not to fail on Java 9. That seems like the best course of action on short term.