NEW TEST(275558@main): [ MacOS iOS ] media/now-playing-webaudio.html …

…is a flaky failure

rdar://124968584
https://bugs.webkit.org/show_bug.cgi?id=271178

Reviewed by Chris Dumez.

Some audio nodes maybe collected even if the audio context is rendering.
This might change the aduio rendering and the now playing info.
Update the test to workaround this until https://bugs.webkit.org/show_bug.cgi?id=271227 is investigated.

* LayoutTests/media/now-playing-webaudio.html:

Canonical link: https://commits.webkit.org/276397@main

LayoutTests/media/now-playing-webaudio.html

@@ -20,19 +20,23 @@
         await waitFor(50);
 }
 
+let context;
+let oscillator;
+let gainNode;
+
 promise_test(async test => {
     if (!window.internals)
         return;
 
     navigator.audioSession.type = "playback";
 
-    let context = new AudioContext();
+    context = new AudioContext();
 
     await waitFor(100);
     assert_false(!!internals.nowPlayingState.uniqueIdentifier);
 
-    let oscillator = null;
-    let gainNode = context.createGain();
+    oscillator = null;
+    gainNode = context.createGain();
     oscillator = context.createOscillator();
     oscillator.type = 'square';
     oscillator.frequency.setValueAtTime(440, context.currentTime);