Update SAXHandlerTest.java

Remove usage of java.util.Objects class due to compatibility issues with Java 5.
Null argument checks introduced,
Merge branch 'MILYN-648' of github.com:michael-krueske/smooks

* 'MILYN-648' of github.com:michael-krueske/smooks:
  Null argument checks introduced,
  Update SAXHandlerTest.java