http/tests/xmlhttprequest/timeout/xmlhttprequest-timeout-overridesexpires.html is flaky

[Alexey Proskuryakov]

http/tests/xmlhttprequest/timeout/xmlhttprequest-timeout-overridesexpires.html flakily fails on slower bots:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=http%2Ftests%2Fxmlhttprequest%2Ftimeout%2Fxmlhttprequest-timeout-overridesexpires.html

-PASS XHR2 Timeout Property Tests 
-PASS XHR2 Timeout Property Tests 1 
+FAIL XHR2 Timeout Property Tests assert_equals: timeout set to expiring value after load fires, original timeout at 1000, reset at 800 to 200 expected "load" but got "timeout"(stack: assert@http://127.0.0.1:8000/w3c/resources/testharness.js:2060:37
+assert_equals@http://127.0.0.1:8000/w3c/resources/testharness.js:699:15
+http://127.0.0.1:8000/xmlhttprequest/timeout/xmlhttprequest-timeout-runner.js:7:40
+step@http://127.0.0.1:8000/w3c/resources/testharness.js:1160:30
+test@http://127.0.0.1:8000/w3c/resources/testharness.js:443:22
+testResultCallbackHandler@http://127.0.0.1:8000/xmlhttprequest/timeout/xmlhttprequest-timeout-runner.js:7:13)
 
This is not very recent, it happened on August 22nd (and possibly before that).

[Alexey Proskuryakov]

Marked as flaky in r189638.

[youenn fablet]

Will have a look at it, probably next week.

FWIW, the timeouts of the corresponding W3C tests got increased 5x, probably for similar reasons (https://github.com/w3c/web-platform-tests/commit/b74228224b0411069050cb81b3d74fc205c59339).

I guess doing so might increase the risk of getting timeouting tests for all xmlhttprequest/timeout tests if not updating TestExpectations.
We might want to try increasing timeouts, by 2x or 3x.

[youenn fablet]

WebKit xmlhttprequest-timeout-overridesexpires.html was removed in favor of WPT version which is not flaky (increased timeouts).