Bug 1546756 - Update WPT expectations following bug 1172394. r=padenot

mediaElementAudioSourceToScriptProcessorTest creates an AudioContext at sample
rate 44100, but that might not be the default cubeb rate on some platforms. If
it isn't, we end up with two MediaTrackGraphs for the same window, with one
being fed by the media element, and the other running the script processor node.
It's when this happens that we only get 0 on the output. We force the preferred
cubeb rate to 44100 for this test, so we at least keep the test coverage of the
media element source node.

This became permafail with bug 1172394, whereas before it was intermittent.
Unclear why.

Differential Revision: https://phabricator.services.mozilla.com/D52050

--HG--
extra : moz-landing-system : lando

testing/web-platform/meta/webaudio/the-audio-api/the-mediaelementaudiosourcenode-interface/mediaElementAudioSourceToScriptProcessorTest.html.ini

@@ -1,8 +0,0 @@
-[mediaElementAudioSourceToScriptProcessorTest.html]
-  disabled:
-    if (os == "mac") and (version == "OS X 10.14"): new platform
-    if (os == "android") and debug: https://bugzilla.mozilla.org/show_bug.cgi?id=1546756
-  [All data processed correctly]
-    expected:
-      if processor == "aarch64": ["PASS", "FAIL"]
-