OMT service worker fetch: Mark a wpt test is flaky

This seems flaky. Update TestExpectations.

Tbr: nhiroki@chromium.org,falken@chromium.org
Bug: 937048
Change-Id: Ibf0b0145af5eb891fa06a3759225cf8cd3ab2a6e
Reviewed-on: https://chromium-review.googlesource.com/c/1496254Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Commit-Queue: Kenichi Ishibashi <bashi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636611}

third_party/blink/web_tests/TestExpectations

@@ -4176,6 +4176,7 @@ crbug.com/435547 http/tests/cachestorage/serviceworker/ignore-search-with-creden
 # This fails because CORS check?: Error message is like:
 # Access to XMLHttpRequest at 'foobar://abcd' (redirected from 'http://web-platform.test:8001/xhr/resources/redirect.py?location=foobar://abcd&code=301') from origin 'http://web-platform.test:8001' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, https.
 crbug.com/924043 virtual/omt-worker-fetch/external/wpt/xhr/send-redirect-bogus-sync.htm [ Timeout ]
+crbug.com/937048 virtual/omt-worker-fetch/external/wpt/service-workers/service-worker/interfaces-sw.https.html [ Pass Timeout ]
 
 crbug.com/697971 [ Mac10.12 ] fast/text/selection/flexbox-selection-nested.html [ Skip ]
 crbug.com/697971 [ Mac10.12 ] fast/text/selection/flexbox-selection.html [ Skip ]