Revert "Temporarily mark external/wpt/fetch/api/response/response-consume-empty.html as flaky"

This reverts commit aad9c7d7.

Reason for revert: upstream change was reverted at
https://github.com/web-platform-tests/wpt/pull/17973

Original change's description:
> Temporarily mark external/wpt/fetch/api/response/response-consume-empty.html as flaky
> 
> https://github.com/web-platform-tests/wpt/pull/17946 is currently blocking
> WPT imports, as the change causes the expected output to change on every
> run.
> 
> Unblock WPT imports by temporarily marking it as flaky while we figure out a
> proper solution.
> 
> TBR=robertma,yhirano
> 
> Bug: 986286
> Change-Id: I0dd6e3f8ef3ab7b50823dcb87cdda9f9e8c9588e
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1713186
> Reviewed-by: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
> Reviewed-by: Robert Ma <robertma@chromium.org>
> Commit-Queue: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
> Cr-Commit-Position: refs/heads/master@{#679579}

TBR=raphael.kubo.da.costa@intel.com,yhirano@chromium.org,robertma@chromium.org

Change-Id: I2ea1381d4ceb61c969fdeedf12f6bda8dcbaf53e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 986286
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1714332Reviewed-by: Robert Ma <robertma@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Robert Ma <robertma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#679967}

third_party/blink/web_tests/TestExpectations

@@ -6341,10 +6341,6 @@ crbug.com/986019 [ Linux ] virtual/threaded/animations/play-state.html [ Pass Ti
 crbug.com/986019 [ Linux ] virtual/disable-blink-gen-property-trees/animations/play-state.html [ Pass Timeout ]
 
 # ecosystem-infra sheriff 2019-07-22
-crbug.com/986286 external/wpt/fetch/api/response/response-consume-empty.html [ Pass Failure ]
-crbug.com/986286 virtual/blink-cors/external/wpt/fetch/api/response/response-consume-empty.html [ Pass Failure ]
-crbug.com/986286 virtual/not-omt-sw-fetch/external/wpt/fetch/api/response/response-consume-empty.html [ Pass Failure ]
-crbug.com/986286 virtual/omt-worker-fetch/external/wpt/fetch/api/response/response-consume-empty.html [ Pass Failure ]
 crbug.com/986457 [ Linux ] http/tests/misc/object-image-error-with-onload.html [ Pass Failure ]
 crbug.com/986477 [ Win ] external/wpt/cookies/path/match.html [ Pass Timeout ]
 crbug.com/986477 [ Win ] virtual/samesite-by-default-cookies/external/wpt/cookies/path/match.html [ Pass Timeout ]
@@ -6356,4 +6352,3 @@ crbug.com/986019 virtual/disable-blink-gen-property-trees/animations/web-animati
 crbug.com/986666 animations/web-animations/animation-state-changes-negative-playback-rate.html [ Pass Failure ]
 crbug.com/986666 virtual/threaded/animations/web-animations/animation-state-changes-negative-playback-rate.html [ Pass Failure ]
 crbug.com/986666 virtual/disable-blink-gen-property-trees/animations/web-animations/animation-state-changes-negative-playback-rate.html [ Pass Failure ]
-