Update SCTP test to use C++ lambdas instead of rtc::Bind

Bug: webrtc:11339
Change-Id: Ibc6818f9d371c17bb6c3e41deee2b51e2b953de0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/201724
Reviewed-by: Taylor <deadbeef@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33018}

media/sctp/sctp_transport_reliability_unittest.cc

@@ -220,16 +220,14 @@ class SctpDataSender final {
       case cricket::SDR_BLOCK:
         // retry after timeout
         invoker_.AsyncInvokeDelayed<void>(
-            RTC_FROM_HERE, thread_,
-            rtc::Bind(&SctpDataSender::SendNextMessage, this), 500);
+            RTC_FROM_HERE, thread_, [this] { SendNextMessage(); }, 500);
         break;
       case cricket::SDR_SUCCESS:
         // send next
         num_bytes_sent_ += payload_.size();
         ++num_messages_sent_;
-        invoker_.AsyncInvoke<void>(
-            RTC_FROM_HERE, thread_,
-            rtc::Bind(&SctpDataSender::SendNextMessage, this));
+        invoker_.AsyncInvoke<void>(RTC_FROM_HERE, thread_,
+                                   [this] { SendNextMessage(); });
         break;
       case cricket::SDR_ERROR:
         // give up