[Sheriff] Expectations for external/wpt/html/dom/interfaces.worker.html

The test is timing out on WebKit Linux Trusty MSAN.
Example
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/WebKit%20Linux%20Trusty%20MSAN/12923

The failure was probably introduced with
https://chromium.googlesource.com/chromium/src/+/69d311c45f95b958dfdf07fd2a48469ca94015d7

Bug: 929122
No-try: True
No-presubmit: True
Change-Id: I494a4c6d9619d368577dd4a4924398d708b27d96
Reviewed-on: https://chromium-review.googlesource.com/c/1482898Reviewed-by: Christos Froussios <cfroussios@chromium.org>
Commit-Queue: Christos Froussios <cfroussios@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634622}

third_party/blink/web_tests/MSANExpectations

@@ -239,3 +239,6 @@ crbug.com/856601 [ Linux ] virtual/disabled-service-worker-servicification/exter
 crbug.com/856601 [ Linux ] virtual/omt-worker-fetch/external/wpt/resource-timing/idlharness.any.html [ Pass Timeout ]
 crbug.com/856601 [ Linux ] virtual/speech-with-unified-autoplay/external/wpt/speech-api/idlharness.window.html [ Pass Timeout ]
 crbug.com/856601 [ Linux ] virtual/unified-autoplay/external/wpt/feature-policy/idlharness.window.html [ Pass Timeout ]
+
+# Sheriff 2019-02-22
+crbug.com/929122 [ Linux ] external/wpt/html/dom/interfaces.worker.html [ Timeout ]