Add manual delete for tra_dbcreators_list (#8207)

* Delete tra_dbcreators_list in ~jrd_tra

If we don't delete it manually assert will be thrown if SEC$DB_CREATORS returns a lot of records

* Add missing default initialization for tra_dbcreators_list

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Co-authored-by: Artyom Ivanov <[email protected]>

Author: TreeHunter9

src/jrd/tra.cpp

@@ -3792,6 +3792,7 @@ jrd_tra::~jrd_tra()
 	delete tra_user_management;
 	delete tra_timezone_snapshot;
 	delete tra_mapping_list;
+	delete tra_dbcreators_list;
 	delete tra_gen_ids;
 
 	if (!tra_outer)

src/jrd/tra.h

@@ -198,6 +198,7 @@ class jrd_tra : public pool_alloc<type_tra>
 		tra_user_management(NULL),
 		tra_sec_db_context(NULL),
 		tra_mapping_list(NULL),
+		tra_dbcreators_list(nullptr),
 		tra_autonomous_pool(NULL),
 		tra_autonomous_cnt(0)
 	{