[QUIC] Do not send multi-port probing when there's no active stream. Limit the max number of multi-port path creations to 5.

PiperOrigin-RevId: 492305120
diff --git a/quiche/quic/core/quic_stream_test.cc b/quiche/quic/core/quic_stream_test.cc
index 1e77c5a..a0837be 100644
--- a/quiche/quic/core/quic_stream_test.cc
+++ b/quiche/quic/core/quic_stream_test.cc
@@ -113,6 +113,8 @@
     stream_ = new StrictMock<TestStream>(kTestStreamId, session_.get(),
                                          BIDIRECTIONAL);
     EXPECT_NE(nullptr, stream_);
+    EXPECT_CALL(*session_, ShouldKeepConnectionAlive())
+        .WillRepeatedly(Return(true));
     // session_ now owns stream_.
     session_->ActivateStream(absl::WrapUnique(stream_));
     // Ignore resetting when session_ is terminated.