Remove empty functions from QSet autotest.

Change-Id: Id6fac3a83e3f4385ee1978a19e6dc92605f4abdb
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

tests/auto/corelib/tools/qset/tst_qset.cpp

@@ -57,10 +57,6 @@ class tst_QSet : public QObject
 {
     Q_OBJECT
 
-public:
-    tst_QSet() {}
-    virtual ~tst_QSet() {}
-
 private slots:
     void operator_eq();
     void swap();