REGRESSION (r252064): [ iOS ] storage/websql/statement-error-callback-isolated-world.html is flaky timing out

[Jacob Uphoff]

storage/websql/statement-error-callback-isolated-world.html is flaky timing out on iOS and started around commit 255123 
I was unable to reproduce the timeout with iterations runs x5000 and running test list from the bot.

History:
https://results.webkit.org/?suite=layout-tests&test=storage%2Fwebsql%2Fstatement-error-callback-isolated-world.html&platform=ios&platform=mac

Diff:

--- /Volumes/Data/slave/ios-simulator-13-release-tests-wk2/build/layout-test-results/storage/websql/statement-error-callback-isolated-world-expected.txt
+++ /Volumes/Data/slave/ios-simulator-13-release-tests-wk2/build/layout-test-results/storage/websql/statement-error-callback-isolated-world-actual.txt
@@ -1,6 +1,8 @@
 CONSOLE MESSAGE: line 6: Web SQL is deprecated. Please use IndexedDB instead.
 CONSOLE MESSAGE: line 45: Web SQL is deprecated. Please use IndexedDB instead.
 ALERT: undefined
-ALERT: PASS: document.body.bar visible in a callback created in this world.
-This test tests that the statement error callback is called in the right world.
+#PID UNRESPONSIVE - WebKitTestRunnerApp (pid 86836)
+FAIL: Timed out waiting for notifyDone to be called
 
+#EOF
+#EOF

[Radar WebKit Bug Importer]

<rdar://problem/58922042>

[Alexey Proskuryakov]

This test had timeout streaks since r252064, so this looks the same as bug 206291.