Revert "[EventTiming] Fix programmatic click test"

This reverts commit 3bd9684c.

Reason for revert: the test
is still flaky https://ci.chromium.org/p/chromium/builders/ci/Mac10.13%20Tests/13241

Original change's description:
> [EventTiming] Fix programmatic click test
> 
> Commits aee8357d and
> faed29aa landed almost at the same time,
> so we accidentally landed a test with the wrong script src for the
> helper functions.
> 
> Bug: 961547
> Change-Id: Id8a615477a54e56139d9d90fc4feb5f780b729a2
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1606225
> Reviewed-by: Liquan (Max) Gu <maxlg@chromium.org>
> Commit-Queue: Nicolás Peña Moreno <npm@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#658761}

TBR=npm@chromium.org,maxlg@chromium.org

Change-Id: I5612c80e93779288839660d8336e6b7ca741732b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 961547
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1606823Reviewed-by: Alexei Filippov <alph@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658834}

third_party/blink/web_tests/TestExpectations

@@ -5551,6 +5551,9 @@ crbug.com/959129 [ Win Linux ] http/tests/devtools/tracing/timeline-script-parse
 # Sheriff 2019-05-07
 crbug.com/960443 [ Mac10.10 Mac10.11 ] external/wpt/animation-worklet/worklet-animation-with-scroll-timeline.https.html [ Failure Pass ]
 
+# Sheriff 2019-05-07
+crbug.com/961547 external/wpt/event-timing/programmatic-click-not-observed.html [ Pass Failure ]
+
 # Sheriff 2019-05-10
 crbug.com/960623 [ Win ] http/tests/misc/resource-timing-sizes-multipart.html [ Pass Failure ]
 

third_party/blink/web_tests/external/wpt/event-timing/programmatic-click-not-observed.html

@@ -8,7 +8,7 @@
 <script src=/resources/testdriver.js></script>
 <script src=/resources/testdriver-vendor.js></script>
 
-<script src=resources/event-timing-test-utils.js></script>
+<script src=resources/event-timing-support.js></script>
 <script>
   let delayCalled = false;
   let beforeClick;