Revert "skip SkipImages unit test on MacOs"

Let's reenable the test for MacOs to see.
The system cache has been purged, a "make distclean" has been done
(see http://nabble.documentfoundation.org/About-skip-SkipImages-unit-test-on-MacOs-td4149788.html)

This reverts commit be01d684.

Change-Id: Ib281db5e3497a3bc9b176a28ccbee25ba051910a

sw/qa/extras/globalfilter/globalfilter.cxx

@@ -45,7 +45,7 @@ public:
     CPPUNIT_TEST(testCharHighlight);
     CPPUNIT_TEST(testMSCharBackgroundEditing);
     CPPUNIT_TEST(testCharBackgroundToHighlighting);
-#if !defined(WNT) && !defined(MACOSX)
+#if !defined(WNT)
     CPPUNIT_TEST(testSkipImages);
 #endif
     CPPUNIT_TEST_SUITE_END();