Disable Assertion messagebox for unittests.

A messagebox will be shown for an assertion in
debug mode. This introduces a need for user
interaction to proceed the execution of the
unit test. Setting the Report mode to debug,
will only print the assertion to stderr.

Change-Id: If8ae80ea96d6608cba77b9c6ca176f97d1680932
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>
Reviewed-by: Jason McDonald <jason.mcdonald@nokia.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>

src/testlib/qtestcase.cpp

@@ -1931,6 +1931,7 @@ int QTest::qExec(QObject *testObject, int argc, char **argv)
 #endif
 
 #if defined(Q_OS_WIN) && !defined(Q_OS_WINCE)
+    _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_DEBUG);
     SetErrorMode(SetErrorMode(0) | SEM_NOGPFAULTERRORBOX);
 #endif