fix: add release save point into execute with batch (#1583)

release auto save points in batch processing in order to avoid out of
shared memory error

fix for the issue #1582

pgjdbc/src/main/java/org/postgresql/core/v3/QueryExecutorImpl.java

@@ -518,6 +518,9 @@ public synchronized void execute(Query[] queries, ParameterList[] parameterLists
 
     try {
       handler.handleCompletion();
+      if (cleanupSavePoints) {
+        releaseSavePoint(autosave, flags);
+      }
     } catch (SQLException e) {
       rollbackIfRequired(autosave, e);
     }