Add appId and stack trace

Author: aboitreaud

dd-java-agent/instrumentation/spark/spark-common/src/main/java/datadog/trace/instrumentation/spark/AbstractSparkInstrumentation.java

@@ -106,6 +106,8 @@ public static void exit(@Advice.Thrown Throwable throwable) {
       if (AbstractDatadogSparkListener.listener != null) {
         AbstractDatadogSparkListener.listener.finishApplication(
             System.currentTimeMillis(), throwable, 0, null);
+      } else {
+        SparkLauncherAdvice.finishSpanWithThrowable(throwable);
       }
     }
   }

dd-java-agent/instrumentation/spark/spark-common/src/main/java/datadog/trace/instrumentation/spark/SparkLauncherAdvice.java

@@ -171,6 +171,7 @@ public void stateChanged(SparkAppHandle handle) {
         String appId = handle.getAppId();
         if (appId != null) {
           span.setTag("spark.app_id", appId);
+          span.setTag("app_id", appId);
         }
 
         if (state.isFinal()) {
@@ -192,6 +193,7 @@ public void infoChanged(SparkAppHandle handle) {
         String appId = handle.getAppId();
         if (appId != null) {
           span.setTag("spark.app_id", appId);
+          span.setTag("app_id", appId);
         }
       }
     }