sheriff: MacOS devtools test to TestExpectations

This change adds the
http/tests/devtools/persistence/persistence-move-breakpoints-on-reload.js
web test to TestExpectations in order to allow the Mac10.13 Tests (dbg)
Builder to be green.

Bug: 1047420

TBR=ioanap@chromium.org,szuend@chromium.org,sigurds@chromium.org

Change-Id: I86ccdb09994d7894176caf0968bc7fb8c63afca9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2031928Reviewed-by: Ovidio de Jesús Ruiz-Henríquez <odejesush@chromium.org>
Commit-Queue: Ovidio de Jesús Ruiz-Henríquez <odejesush@chromium.org>
Cr-Commit-Position: refs/heads/master@{#737018}

third_party/blink/web_tests/TestExpectations

@@ -6510,3 +6510,4 @@ crbug.com/1047164 [ Mac ] fast/scroll-snap/snaps-after-keyboard-scrolling.html [
 crbug.com/1047208 virtual/omt-service-worker-startup/http/tests/serviceworker/update-served-from-cache.html [ Pass Failure ]
 crbug.com/1047208 http/tests/serviceworker/update-served-from-cache.html [ Pass Failure ]
 crbug.com/1047293 [ Mac ] editing/pasteboard/pasteboard_with_unfocused_selection.html [ Pass Failure ]
+crbug.com/1047420 [ Mac ] http/tests/devtools/persistence/persistence-move-breakpoints-on-reload.js [ Pass Failure ]