Disable flakey test on Mac: PreconnectNotSearchBackgroundForeground

NavigationPredictorPreconnectClientBrowserTest
.PreconnectNotSearchBackgroundForeground is flakey on mac, see bug for
details.

TBR=ryansturm@chromium.org

Bug: 1061932
Change-Id: I23de7d1b8aec2cfa34ae9b2c2d2f6c855a961171
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2105418Reviewed-by: James MacLean <wjmaclean@chromium.org>
Commit-Queue: James MacLean <wjmaclean@chromium.org>
Cr-Commit-Position: refs/heads/master@{#750576}

chrome/browser/navigation_predictor/navigation_predictor_preconnect_client_browsertest.cc

@@ -128,8 +128,15 @@ IN_PROC_BROWSER_TEST_F(NavigationPredictorPreconnectClientBrowserTest,
   EXPECT_EQ(2, preresolve_done_count_);
 }
 
+#if defined(OS_MACOSX)
+#define MAYBE_PreconnectNotSearchBackgroundForeground \
+  DISABLED_PreconnectNotSearchBackgroundForeground
+#else
+#define MAYBE_PreconnectNotSearchBackgroundForeground \
+  PreconnectNotSearchBackgroundForeground
+#endif
 IN_PROC_BROWSER_TEST_F(NavigationPredictorPreconnectClientBrowserTest,
-                       PreconnectNotSearchBackgroundForeground) {
+                       MAYBE_PreconnectNotSearchBackgroundForeground) {
   const GURL& url = GetTestURL("/anchors_different_area.html");
 
   browser()->tab_strip_model()->GetActiveWebContents()->WasHidden();