Disable the flaky test SplitCacheDedicatedWorkerScripts on macOS

TBR=agl@chromium.org

Bug: 997732
Bug: 1105733
Change-Id: Iab83322d35a5e24f3ea1ee5bbdb25daae33ecc60
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2298961Reviewed-by: Hajime Hoshi <hajimehoshi@chromium.org>
Commit-Queue: Hajime Hoshi <hajimehoshi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#788499}

content/browser/net/split_cache_browsertest.cc

@@ -762,8 +762,8 @@ IN_PROC_BROWSER_TEST_P(SplitCacheContentBrowserTestEnabled,
       GenURL("e.com", "/worker.js")));
 }
 
-// TODO(http://crbug.com/997732): Flaky on Linux.
-#if defined(OS_LINUX)
+// TODO(http://crbug.com/997732): Flaky on Linux and macOS.
+#if defined(OS_LINUX) || defined(OS_MACOSX)
 #define MAYBE_SplitCacheDedicatedWorkerScripts \
   DISABLED_SplitCacheDedicatedWorkersScripts
 #else