Improve logging for BandwidthSampler map size bug entry.

gfe-relnote: extra details in a GFE_BUG call.  Not flag-protected.
PiperOrigin-RevId: 263353963
Change-Id: Ie039f8d91fea6b79796975e975b9cc9d6c0a9c73
diff --git a/quic/core/congestion_control/bandwidth_sampler_test.cc b/quic/core/congestion_control/bandwidth_sampler_test.cc
index 9e36bdc..aeff976 100644
--- a/quic/core/congestion_control/bandwidth_sampler_test.cc
+++ b/quic/core/congestion_control/bandwidth_sampler_test.cc
@@ -33,7 +33,8 @@
 class BandwidthSamplerTest : public QuicTest {
  protected:
   BandwidthSamplerTest()
-      : sampler_(/*max_height_tracker_window_length=*/0), bytes_in_flight_(0) {
+      : sampler_(nullptr, /*max_height_tracker_window_length=*/0),
+        bytes_in_flight_(0) {
     // Ensure that the clock does not start at zero.
     clock_.AdvanceTime(QuicTime::Delta::FromSeconds(1));
   }