Mark BrowserNavigatorTest.SingletonProfileLeak as flaky on Linux

BrowserNavigatorTest.SingletonProfileLeak fails on browser_tests,
viz_browser_tests, site_per_process_browser_tests, and
network_service_browser_tests.  Failures seen on "Linux Tests (dbg)(1)" and
"Linux Tests (dbg)(1)(32)".

Failures:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Tests%20%28dbg%29%281%29/70940
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Tests%20%28dbg%29%281%29/70937
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Linux%20Tests%20%28dbg%29%281%29/70933
https://ci.chromium.org/buildbot/chromium.linux/Linux%20Tests%20%28dbg%29%281%29%2832%29/48775
https://ci.chromium.org/buildbot/chromium.linux/Linux%20Tests%20%28dbg%29%281%29%2832%29/48771
https://ci.chromium.org/buildbot/chromium.linux/Linux%20Tests%20%28dbg%29%281%29%2832%29/48767

BUG=822033
TBR=sky

Change-Id: I90a1c3d76eab9139d70f0b8da0a22cf883e1d32f
Reviewed-on: https://chromium-review.googlesource.com/963090Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543248}

chrome/browser/ui/browser_navigator_browsertest.cc

@@ -757,7 +757,13 @@ IN_PROC_BROWSER_TEST_F(BrowserNavigatorTest, SingletonWindowLeak) {
 // Tests that a disposition of SINGLETON_TAB cannot see outside its
 // window, and that a disposition of SWITCH_TO_TAB can't see outside
 // its profile, except for certain non-incognito affinity URLs.
-IN_PROC_BROWSER_TEST_F(BrowserNavigatorTest, SingletonProfileLeak) {
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+// https://crbug.com/822033
+#define MAYBE_SingletonProfileLeak DISABLED_SingletonProfileLeak
+#else
+#define MAYBE_SingletonProfileLeak SingletonProfileLeak
+#endif
+IN_PROC_BROWSER_TEST_F(BrowserNavigatorTest, MAYBE_SingletonProfileLeak) {
   Browser* orig_browser;
 
   // Navigate to a site.