[Gluten-986] Metric "time to collect" is always 0 in ColumnarBroadcas…

…tExchange (#989)

Remove totalTime, fix collectTime, add buildTime.
Gluten uses BackendsApiManager.getSparkPlanExecApiInstance.createBroadcastRelation to collect data and build relation, we don't have to separate collectTime and buildTime, cause they are almost equal.

Closes #986

gluten-core/src/main/scala/org/apache/spark/sql/execution/ColumnarBroadcastExchangeExec.scala

@@ -42,8 +42,7 @@ case class ColumnarBroadcastExchangeExec(mode: BroadcastMode, child: SparkPlan)
   extends BroadcastExchangeLike {
   override lazy val metrics = Map(
     "dataSize" -> SQLMetrics.createSizeMetric(sparkContext, "data size"),
-    "numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of Rows"),
-    "totalTime" -> SQLMetrics.createTimingMetric(sparkContext, "totaltime_broadcastExchange"),
+    "numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"),
     "collectTime" -> SQLMetrics.createTimingMetric(sparkContext, "time to collect"),
     "broadcastTime" -> SQLMetrics.createTimingMetric(sparkContext, "time to broadcast")
   )
@@ -66,6 +65,7 @@ case class ColumnarBroadcastExchangeExec(mode: BroadcastMode, child: SparkPlan)
           runId.toString,
           s"broadcast exchange (runId $runId)",
           interruptOnCancel = true)
+        val beforeCollect = System.nanoTime()
 
         // this created relation ignore HashedRelationBroadcastMode isNullAware, because we cannot
         // get child output rows, then compare the hash key is null, if not null, compare the
@@ -76,16 +76,13 @@ case class ColumnarBroadcastExchangeExec(mode: BroadcastMode, child: SparkPlan)
           child,
           longMetric("numOutputRows"),
           longMetric("dataSize"))
-        val beforeCollect = System.nanoTime()
         val beforeBroadcast = System.nanoTime()
 
         longMetric("collectTime") += NANOSECONDS.toMillis(beforeBroadcast - beforeCollect)
 
         // Broadcast the relation
         val broadcasted = sparkContext.broadcast(relation.asInstanceOf[Any])
         longMetric("broadcastTime") += NANOSECONDS.toMillis(System.nanoTime() - beforeBroadcast)
-        longMetric("totalTime").merge(longMetric("collectTime"))
-        longMetric("totalTime").merge(longMetric("broadcastTime"))
 
         // Update driver metrics
         val executionId = sparkContext.getLocalProperty(SQLExecution.EXECUTION_ID_KEY)