DevTools: mark test as flaky http/tests/devtools/console-focus.js

TBR=luoe@chromium.org

Bug: 789225
Change-Id: I1453c23aa6ccd1c5db9b96423e8e5d9061bc412f
Reviewed-on: https://chromium-review.googlesource.com/794393
Commit-Queue: Will Chen <chenwilliam@chromium.org>
Reviewed-by: Will Chen <chenwilliam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#519812}

third_party/WebKit/LayoutTests/TestExpectations

@@ -774,6 +774,9 @@ crbug.com/785571 virtual/mojo-loading/http/tests/devtools/console/console-contex
 
 # ====== DevTools test migration failures until here ======
 
+crbug.com/789225 http/tests/devtools/console/console-focus.js [ Pass Failure ]
+crbug.com/789225 virtual/mojo-loading/http/tests/devtools/console/console-focus.js [ Pass Failure ]
+
 crbug.com/667560 [ Win ] http/tests/devtools/console-cross-origin-iframe-logging.js [ Pass Timeout ]
 crbug.com/667560 [ Win ] virtual/mojo-loading/http/tests/devtools/console-cross-origin-iframe-logging.js [ Pass Timeout ]