sc: disable "forecast.ets.add.fods" test file on Macs

This sometimes fails, since months, and nobody has fixed it.
Let's improve the reliability of CI a bit.

Change-Id: Ic4d2e085151855d35804f8ed6ebca04366815c0b
Reviewed-on: https://gerrit.libreoffice.org/49144
Reviewed-by: Eike Rathke <erack@redhat.com>
Tested-by: Jenkins <ci@libreoffice.org>

sc/qa/unit/functions_test.cxx

@@ -40,6 +40,10 @@ bool FunctionsTest::load(const OUString& rFilter, const OUString& rURL,
 
     ScDocument& rDoc = xDocShRef->GetDocument();
 
+#ifdef __APPLE__
+// FIXME tends to fail a lot
+if (!rURL.endsWith("forecast.ets.add.fods"))
+#endif
     CPPUNIT_ASSERT_DOUBLES_EQUAL(1.0, rDoc.GetValue(1, 2, 0), 1e-14);
 
     xDocShRef->DoClose();