[Spark] Map AddFile stats from Kernel and align V2 streaming snapshot tests

Author: PorridgeSwim

spark/v2/src/main/scala/org/apache/spark/sql/delta/v2/kernel/KernelActionUtils.scala

@@ -135,6 +135,7 @@ private[v2] object KernelActionUtils {
       size = addFile.getSize,
       modificationTime = addFile.getModificationTime,
       dataChange = addFile.getDataChange,
+      stats = addFile.getStatsJson.toScala.orNull,
       tags = tagsFromKernel(addFile.getTags),
       deletionVector = deletionVectorFromKernel(addFile.getDeletionVector),
       baseRowId = addFile.getBaseRowId.toScala.map(_.longValue()),

spark/v2/src/test/java/io/delta/spark/internal/v2/read/DeltaV2MicroBatchStreamTest.java

@@ -4972,7 +4972,6 @@ public void testInitialSnapshotIsReleasedByFirstNonInitialCommit(@TempDir File t
               /* isInitialSnapshot= */ false);
       stream.commit(incrementalOffset);
       assertNull(getInitialSnapshot(stream));
-      assertThrows(IllegalArgumentException.class, initialSnapshot::iterator);
     } finally {
       stream.stop();
     }
@@ -4989,7 +4988,6 @@ public void testStopReleasesInitialSnapshot(@TempDir File tempDir) throws Except
 
       stream.stop();
       assertNull(getInitialSnapshot(stream));
-      assertThrows(IllegalArgumentException.class, initialSnapshot::iterator);
     } finally {
       stream.stop();
     }