[tools/perf] Disable multitab:misc:typical24 on Mac

TBR=nednguyen@google.com

Bug: 742475
Change-Id: I5c4e2e05c45c835e9163cfd5f2e47ee958298064
Reviewed-on: https://chromium-review.googlesource.com/574916Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487433}

tools/perf/page_sets/system_health/expectations.py

@@ -48,6 +48,8 @@ class SystemHealthDesktopMemoryExpectations(expectations.StoryExpectations):
                       [expectations.ALL_MAC], 'crbug.com/728576')
     self.DisableStory('browse:social:twitter_infinite_scroll',
                       [expectations.ALL_WIN], 'crbug.com/728464')
+    self.DisableStory('multitab:misc:typical24',
+                      [expectations.ALL_MAC], 'crbug.com/742475')
 
 
 class SystemHealthMobileCommonExpectations(expectations.StoryExpectations):