[macOS] TestWebKitAPI.WebKit.MediaBufferingPolicy is a constant failure

https://bugs.webkit.org/show_bug.cgi?id=253658
rdar://problem/106508946

Reviewed by Jer Noble.

macOS shouldn't purge media playback resources on page suspension.
This behavior was changed in 261354@main. This is just aligning the test
case

* Tools/TestWebKitAPI/Tests/WebKitCocoa/MediaBufferingPolicy.mm:
(TEST):

Canonical link: https://commits.webkit.org/262438@main

Author: salinas-miguel

Tools/TestWebKitAPI/Tests/WebKitCocoa/MediaBufferingPolicy.mm

@@ -68,7 +68,12 @@ static void waitUntilBufferingPolicyIsEqualTo(WKWebView* webView, const char* ex
 
     // Suspending the process also forces a memory warning, which should purge whatever possible ASAP.
     [webView _processWillSuspendImminentlyForTesting];
+#if PLATFORM(MAC)
+    // Suspending the page on macOS shouldn't cause resource purging
+    waitUntilBufferingPolicyIsEqualTo(webView.get(), "Default");
+#else
     waitUntilBufferingPolicyIsEqualTo(webView.get(), "PurgeResources");
+#endif
 
     // And should switch back to default when buffering is allowed.
     [webView _processDidResumeForTesting];