feat: support PartialMerge

Author: comphead

spark/src/test/scala/org/apache/comet/exec/CometExecSuite.scala

@@ -484,8 +484,7 @@ class CometExecSuite extends CometTestBase {
         case s: CometHashAggregateExec => s
       }.get
 
-      assert(
-        agg.modes.nonEmpty && agg.modes.headOption.get.isInstanceOf[AggregateMode])
+      assert(agg.modes.nonEmpty && agg.modes.headOption.get.isInstanceOf[AggregateMode])
       val newAgg = agg.cleanBlock().asInstanceOf[CometHashAggregateExec]
       assert(
         newAgg.modes.nonEmpty &&