TestWebKitAPI.AVFoundationPref.PrefTest seems flaky. In https://ews-build.webkit-uat.org/#/builders/20/builds/2192, the test Failed in run-api-tests step. However, in the immediately next retry step (re-run-api-tests), it passed.
<rdar://problem/50509878>
This test was added in http://trac.webkit.org/changeset/229995/webkit