Disable VideoSendStreamTest.MinTransmitBitrateRespectsRemb in Mac.

Test is flaky there, especially with the task queue pacer enabled.

Bug: webrtc:13294
Change-Id: I1b2fdbbf6b760bd0cbeb8992442549c7d50abb09
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/235660
Reviewed-by: Evan Shrubsole <eshr@webrtc.org>
Commit-Queue: Evan Shrubsole <eshr@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35232}
diff --git a/video/video_send_stream_tests.cc b/video/video_send_stream_tests.cc
index 294181e..b0394f8 100644
--- a/video/video_send_stream_tests.cc
+++ b/video/video_send_stream_tests.cc
@@ -1458,7 +1458,14 @@
 //
 // Note that the test starts at "high" bitrate and does not ramp up to "higher"
 // bitrate since no receiver block or remb is sent in the initial phase.
-TEST_F(VideoSendStreamTest, MinTransmitBitrateRespectsRemb) {
+// TODO(bugs.webrtc.org/13294): Fix flakiness or replace with scenario test.
+#if defined(WEBRTC_MAC)
+#define MAYBE_MinTransmitBitrateRespectsRemb \
+  DISABLED_MinTransmitBitrateRespectsRemb
+#else
+#define MAYBE_MinTransmitBitrateRespectsRemb MinTransmitBitrateRespectsRemb
+#endif
+TEST_F(VideoSendStreamTest, MAYBE_MinTransmitBitrateRespectsRemb) {
   static const int kMinTransmitBitrateBps = 400000;
   static const int kHighBitrateBps = 150000;
   static const int kRembBitrateBps = 80000;