Make tst_QFont::italicOblique failures easier to debug

It fails locally for me on Lucida Calligraphy.
Lucida Calligraphy only has one style though: Italic.

Change-Id: I42442cb922132a00f09084cef9c739196a9a53c2
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

tests/auto/gui/text/qfont/tst_qfont.cpp

@@ -150,7 +150,7 @@ void tst_QFont::italicOblique()
                     continue;
                 }
                 QFont f = QFontDatabase::font(family, style, 12);
-                QVERIFY(f.italic());
+                QVERIFY2(f.italic(), qPrintable(QString::asprintf("Failed for font \"%ls\"", f.family().utf16())));
             }
         }
     }