Layout Test js/error-should-not-strong-reference-global-object.html is a flaky failure

[Ryan Haddad]

The following layout test is flaky on iOS and macOS

js/error-should-not-strong-reference-global-object.html

Probable cause:

This test was added with https://trac.webkit.org/changeset/232314/webkit and appears to have been flaky since the start.

Flakiness Dashboard:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=js%2Ferror-should-not-strong-reference-global-object.html

--- /Volumes/Data/slave/highsierra-release-tests-wk1/build/layout-test-results/js/error-should-not-strong-reference-global-object-expected.txt
+++ /Volumes/Data/slave/highsierra-release-tests-wk1/build/layout-test-results/js/error-should-not-strong-reference-global-object-actual.txt
@@ -1,4 +1,5 @@
-PASS successfullyParsed is true
+CONSOLE MESSAGE: line 46: Error: There are more global objects than there should be
+FAIL successfullyParsed should be true (of type boolean). Was undefined (of type undefined).
 
 TEST COMPLETE

[Ryan Haddad]

The test is terribly flaky and making the bots red. Keith, would you take a look at this? We need to fix the test or roll out the change.

[Ryan Haddad]

The same change seems to have introduced flakiness in another test:
https://bugs.webkit.org/show_bug.cgi?id=186161

[Mark Lam]

Landed a speculative fix in r232810: <http://trac.webkit.org/r232810>.

Please re-open or file a new bug if this test is still flaky.

[Radar WebKit Bug Importer]

<rdar://problem/41101615>