[IntersectionObserver] Update WPTs to the latest upstream version
https://bugs.webkit.org/show_bug.cgi?id=189515
Reviewed by Youenn Fablet.
* web-platform-tests/intersection-observer/initial-observation-with-threshold-expected.txt: Added.
* web-platform-tests/intersection-observer/initial-observation-with-threshold.html: Added.
* web-platform-tests/intersection-observer/resources/intersection-observer-test-utils.js:
(waitForNotification):
* web-platform-tests/intersection-observer/w3c-import.log:
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@235923
268f45cc-cd09-0410-ab3c-
d52691b4dbfc