Disable flaky tests on on Android FYI SkiaRenderer Vulkan (Pixel 2)

The following tests are flaky. Disabling them for now.
MediaSourceTest.Playback_VideoAudio_WebM
WebRtcDataBrowserTest.CallWithSctpDataAndMedia
WebRtcDataBrowserTest.CallWithDataAndMedia

Bug: 990116
Change-Id: I6164f487483ea1a5cb74490553146ca0c1dfb59b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1730784
Commit-Queue: Eric Karl <ericrk@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>
Auto-Submit: Eric Karl <ericrk@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683412}

testing/buildbot/filters/gpu.skiarenderer_vulkan_content_browsertests.filter

@@ -90,3 +90,9 @@
 -MSE_ClearKey/EncryptedMediaTest.FrameSizeChangeVideo/0
 -MSE_ExternalClearKey/EncryptedMediaTest.FrameSizeChangeVideo/0
 -File/MediaTest.VideoBearSilentMp4/0
+
+# crbug.com/990116: vulkan_content_browsertests experience flaky failures for
+# these tests.
+-MediaSourceTest.Playback_VideoAudio_WebM
+-WebRtcDataBrowserTest.CallWithSctpDataAndMedia
+-WebRtcDataBrowserTest.CallWithDataAndMedia