Enable cursor in ligature test on Windows

The default font on Windows ("Times" is not found) does not have
a ligature for "fi", so the test would not actually be testing
what it was supposed to on this platform, and would pass even
when the code was buggy.

To enable the test on Windows, we select a standard font which
has the ligature (Calibri).

Change-Id: Ic117cd8e549aa729a0cd68006d7c180c6c89c053
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

tests/auto/gui/text/qtextlayout/tst_qtextlayout.cpp

@@ -2068,7 +2068,12 @@ void tst_QTextLayout::cursorInLigatureWithMultipleLines()
 
 void tst_QTextLayout::xToCursorForLigatures()
 {
+#if defined(Q_OS_WIN32)
+    QTextLayout layout("fi", QFont("Calibri", 20));
+#else
     QTextLayout layout("fi", QFont("Times", 20));
+#endif
+
     layout.setCacheEnabled(true);
     layout.beginLayout();
     QTextLine line = layout.createLine();