Improve QuicConnectionTest test times

Certain QuicConnectionTest tests result in warnings like the following:

```
GMOCK WARNING:
../../net/third_party/quiche/src/quiche/quic/core/quic_connection_test.cc:2609: Actions ran out in EXPECT_CALL(*send_algorithm_, OnPacketSent(_, _, _, _, _))...
Called 2 times, but only 1 WillOnce() is specified - returning directly.
Stack trace:
...
```

Stack trace symbolization takes a long time in Chromium unit tests (see https://crbug.com/340987671), so avoiding these warnings reduces the test execution times from seconds to a few milliseconds. IIUC the changes in this CL don't affect the test behavior and just suppress the warnings.

Affected tests with test execution times from my gLinux cloudtop:

 - NoNonProbingFrameOnAlternativePath (41385 ms)
 - ReceivePathProbingFromNewPeerAddressAtServer (9948 ms)
 - ClientResponseToPathChallengeOnAlternativeSocket (2266 ms)
 - DuplicateAckCausesLostPackets (1991 ms)
 - PathValidationOnNewSocketSuccess (2241 ms)
 - PathValidationReceivesStatelessReset (2289 ms)
 - SendPathChallengeUsingBlockedNewSocket (2215 ms)
 - PathChallengeBeforePeerIpAddressChangeAtServer (2284 ms)
 - DetectSimutanuousServerAndClientAddressChangeWithProbe (2358 ms)

All the tests above are parameterized with similar test execution times for the following variants:
 - RFCv2_defer
 - RFCv2_immediate
 - RFCv1_defer
 - RFCv1_immediate
 - draft29_defer
 - draft29_immediate

The DuplicateAckCausesLostPackets test was also slow for the Q046_defer variant.

PiperOrigin-RevId: 650281559
diff --git a/quiche/quic/core/quic_connection_test.cc b/quiche/quic/core/quic_connection_test.cc
index decb72d..28bb07c 100644
--- a/quiche/quic/core/quic_connection_test.cc
+++ b/quiche/quic/core/quic_connection_test.cc
@@ -62,6 +62,7 @@
 using testing::AnyNumber;
 using testing::AtLeast;
 using testing::DoAll;
+using testing::DoDefault;
 using testing::ElementsAre;
 using testing::Ge;
 using testing::IgnoreResult;
@@ -2611,7 +2612,8 @@
           EXPECT_EQ(1u, writer_->path_challenge_frames().size());
           EXPECT_EQ(1u, writer_->path_response_frames().size());
           payload = writer_->path_challenge_frames().front().data_buffer;
-        }));
+        }))
+        .WillRepeatedly(DoDefault());
   }
   // Process a probing packet from a new peer address on server side
   // is effectively receiving a connectivity probing.
@@ -8770,7 +8772,9 @@
         EXPECT_EQ(1u, new_writer.padding_frames().size());
         EXPECT_EQ(kNewSelfAddress.host(),
                   new_writer.last_write_source_address());
-      }));
+      }))
+      .WillRepeatedly(DoDefault());
+  ;
   std::unique_ptr<SerializedPacket> probing_packet = ConstructProbingPacket();
   std::unique_ptr<QuicReceivedPacket> received(ConstructReceivedPacket(
       QuicEncryptedPacket(probing_packet->encrypted_buffer,
@@ -11365,7 +11369,9 @@
   EXPECT_CALL(*loss_algorithm_, DetectLosses(_, _, _, _, _, _))
       .Times(AnyNumber())
       .WillOnce(DoAll(SetArgPointee<5>(lost_packets),
-                      Return(LossDetectionInterface::DetectionStats())));
+                      Return(LossDetectionInterface::DetectionStats())))
+      .WillRepeatedly(DoDefault());
+  ;
   ProcessAckPacket(1, &frame);
   EXPECT_TRUE(connection_.BlackholeDetectionInProgress());
   QuicAlarm* retransmission_alarm = connection_.GetRetransmissionAlarm();
@@ -11489,7 +11495,9 @@
         EXPECT_EQ(1u, new_writer.padding_frames().size());
         EXPECT_EQ(kNewSelfAddress.host(),
                   new_writer.last_write_source_address());
-      }));
+      }))
+      .WillRepeatedly(DoDefault());
+  ;
   bool success = false;
   connection_.ValidatePath(
       std::make_unique<TestQuicPathValidationContext>(
@@ -11660,7 +11668,9 @@
         EXPECT_EQ(1u, new_writer.padding_frames().size());
         EXPECT_EQ(kNewSelfAddress.host(),
                   new_writer.last_write_source_address());
-      }));
+      }))
+      .WillRepeatedly(DoDefault());
+  ;
   bool success = true;
   connection_.ValidatePath(
       std::make_unique<TestQuicPathValidationContext>(
@@ -11705,7 +11715,9 @@
         EXPECT_EQ(1u, new_writer.padding_frames().size());
         EXPECT_EQ(kNewSelfAddress.host(),
                   new_writer.last_write_source_address());
-      }));
+      }))
+      .WillRepeatedly(DoDefault());
+  ;
   bool success = false;
   connection_.ValidatePath(
       std::make_unique<TestQuicPathValidationContext>(
@@ -14010,7 +14022,9 @@
         EXPECT_FALSE(writer_->path_response_frames().empty());
         EXPECT_FALSE(writer_->path_challenge_frames().empty());
         payload = writer_->path_challenge_frames().front().data_buffer;
-      }));
+      }))
+      .WillRepeatedly(DoDefault());
+  ;
   ProcessFramesPacketWithAddresses(frames1, kSelfAddress, kNewPeerAddress,
                                    ENCRYPTION_FORWARD_SECURE);
   EXPECT_EQ(kPeerAddress, connection_.peer_address());
@@ -14277,7 +14291,6 @@
   QuicFrames frames1;
   frames1.push_back(
       QuicFrame(QuicPathChallengeFrame(0, path_challenge_payload)));
-  QuicPathFrameBuffer payload;
   EXPECT_CALL(*send_algorithm_,
               OnPacketSent(_, _, _, _, NO_RETRANSMITTABLE_DATA))
       .Times(AtLeast(1))
@@ -14287,8 +14300,8 @@
         EXPECT_EQ(kPeerAddress, connection_.effective_peer_address());
         EXPECT_FALSE(writer_->path_response_frames().empty());
         EXPECT_FALSE(writer_->path_challenge_frames().empty());
-        payload = writer_->path_challenge_frames().front().data_buffer;
-      }));
+      }))
+      .WillRepeatedly(DoDefault());
   ProcessFramesPacketWithAddresses(frames1, kSelfAddress, kNewPeerAddress,
                                    ENCRYPTION_FORWARD_SECURE);
   EXPECT_EQ(kPeerAddress, connection_.peer_address());
@@ -17256,7 +17269,8 @@
         EXPECT_EQ(kServerPreferredAddress.host(),
                   writer_->last_write_source_address());
         EXPECT_EQ(kNewPeerAddress, writer_->last_write_peer_address());
-      }));
+      }))
+      .WillRepeatedly(DoDefault());
   ProcessReceivedPacket(kServerPreferredAddress, kNewPeerAddress, *received);
   EXPECT_EQ(num_probing_received + 1,
             connection_.GetStats().num_connectivity_probing_received);