Fix flaky test in QuicSessionTest. Port of

net/quic/quic_session_test.cc

Index: net/quic/quic_session_test.cc
diff --git a/net/quic/quic_session_test.cc b/net/quic/quic_session_test.cc
index 77a9e89e623666e2eb4d85318dc549d987f3b1ad..5f020164eeb395b0a20bf4cf4dcc3647104a7e04 100644
--- a/net/quic/quic_session_test.cc
+++ b/net/quic/quic_session_test.cc
@@ -739,7 +739,7 @@ TEST_P(QuicSessionTest, HandshakeUnblocksFlowControlBlockedHeadersStream) {
     headers_stream->WriteHeaders(stream_id, headers, true, nullptr);
     stream_id += 2;
   }
-  // Write one more to ensure that the headers stream has buffered data. The
+  // Write once more to ensure that the headers stream has buffered data. The
   // random headers may have exactly filled the flow control window.
   headers_stream->WriteHeaders(stream_id, headers, true, nullptr);
   EXPECT_TRUE(headers_stream->HasBufferedData());