[Sheriff] Disable flaky test BrowserTest.WindowOpenClose2 on Linux

Test is flaking consistently on the CQ:
https://chromium-try-flakes.appspot.com/all_flake_occurrences?key=ahVzfmNocm9taXVtLXRyeS1mbGFrZXNyJwsSBUZsYWtlIhxCcm93c2VyVGVzdC5XaW5kb3dPcGVuQ2xvc2UyDA

TBR=fsamuel@chromium.org

Bug: 823043
Change-Id: I6103eb9fcb95e9e3afc77ab9da1740391fe5d211
Reviewed-on: https://chromium-review.googlesource.com/1151387Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578299}

chrome/browser/ui/browser_browsertest.cc

@@ -1885,8 +1885,8 @@ IN_PROC_BROWSER_TEST_F(BrowserTest, MAYBE_WindowOpenClose1) {
   EXPECT_EQ(title, title_watcher.WaitAndGetTitle());
 }
 
-// Flaky on Chrome OS and Windows. TODO(https://crbug.com/823043) fix it.
-#if defined(OS_CHROMEOS) || defined(OS_WIN)
+// Flaky on Chrome OS, Linux and Windows. TODO(https://crbug.com/823043) fix it.
+#if defined(OS_CHROMEOS) || defined(OS_LINUX) || defined(OS_WIN)
 #define MAYBE_WindowOpenClose2 DISABLED_WindowOpenClose2
 #else
 #define MAYBE_WindowOpenClose2 WindowOpenClose2