public static JsonObject buildStatSummary(RTCStatMap statMap) {
    return buildStatSummary(statMap, false);
  }
Returns the test's getSDPMessageScript to retrieve the sdp message for either the offer or answer.
If it doesn't exist then the method returns 'unknown'.

@return the getSDPMessageScript as string.
KITE-Framework/src/main/java/org/webrtc/kite/stats/StatsUtils.java