sw: make CppunitTest_sw_uwriter a slowcheck

It's annoying that after touching a cxx file from Library_sw, it's not
enough to wait till it relinks, it also relinks CppunitTest_sw_uwriter
as well. So turn that one into a slowcheck, this way 'make sw' doesn't
relink it.

Change-Id: I0a8d956f57e92a9c6f1f91b727f492ca4c92c599

sw/Module_sw.mk

@@ -46,11 +46,8 @@ $(eval $(call gb_Module_add_targets,sw,\
 
 endif
 
-$(eval $(call gb_Module_add_check_targets,sw,\
-    CppunitTest_sw_uwriter \
-))
-
 $(eval $(call gb_Module_add_slowcheck_targets,sw,\
+    CppunitTest_sw_uwriter \
     CppunitTest_sw_htmlexport \
     CppunitTest_sw_macros_test \
     CppunitTest_sw_ooxmlexport \