test: skipped unstable portion of tst_qcssparser on qpa

This test unstably fails because font lookup is somewhat broken for qpa.

Task-number: QTBUG-20986
Change-Id: Id4ebd35e979d8837d32b58e5ed9c1df3ac15827a
Reviewed-on: http://codereview.qt.nokia.com/3130
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Kalle Lehtonen <kalle.ju.lehtonen@nokia.com>

tests/auto/qcssparser/tst_qcssparser.cpp

@@ -1590,6 +1590,14 @@ void tst_QCssParser::extractFontFamily()
     QFont fnt;
     extractor.extractFont(&fnt, &adjustment);
     QFontInfo info(fnt);
+
+#ifdef Q_WS_QPA
+    // Note, we have to QSKIP rather than QEXPECT_FAIL because font lookup is broken
+    // such that it may work or not work depending on the order in which fonts were
+    // loaded from disk
+    QSKIP("QTBUG-20986 may fail on qpa", SkipSingle);
+#endif
+
     QTEST(info.family(), "expectedFamily");
 }