Disable flaky call_perf tests for iOS devices

These tests fail occasionally on iOS real devices in swarming.
See bug for details.

Bug: webrtc:10417
Change-Id: Ie33ee7dcb2b637540c9d7c032b1929c1f08d1dc4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/128087
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Artem Titarenko <artit@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27182}

call/call_perf_tests.cc

@@ -318,7 +318,10 @@ void CallPerfTest::TestAudioVideoSync(FecMode fec,
 
   // In quick test synchronization may not be achieved in time.
   if (!field_trial::IsEnabled("WebRTC-QuickPerfTest")) {
+// TODO(bugs.webrtc.org/10417): Reenable this for iOS
+#if !defined(WEBRTC_IOS)
     EXPECT_EQ(1, metrics::NumSamples("WebRTC.Video.AVSyncOffsetInMs"));
+#endif
   }
 }