Bug 599378: Disabled test_hanging.html on Mac OS X for now. a=josh

modules/plugin/test/mochitest/Makefile.in

@@ -85,7 +85,6 @@ _MOCHITEST_FILES = \
   neverending.sjs \
   test_newstreamondestroy.html \
   $(warning test_crashing2.html disabled due to random orange; see bug 566049) \
-  test_hanging.html \
   crashing_subpage.html \
   test_GCrace.html \
   test_propertyAndMethod.html \
@@ -122,10 +121,12 @@ endif
 endif
 endif
 
-# Temporarily disable these tests on Mac OS X, see bug 599076 and bug 599267.
+# Temporarily disable these tests on Mac OS X, see bug 599076 and bug 599267
+# and bug 599378.
 ifneq (cocoa,$(MOZ_WIDGET_TOOLKIT))
 _MOCHITEST_FILES += \
   test_crashing.html \
+  test_hanging.html \
   $(NULL)
 
 _MOCHICHROME_FILES += \