IOSS: Update db_zone property after reopening cgns database
The CGNS library will reorder (sort) zones based on their names, so if an application defines zones to an output file; closes that file and then reopens the file, the zones on the file will have a different ordering or indexing than when they were originally defined on the file. This commit causes the IOSS library to update the `db_zone` property on all StructuredBlocks and ElementBlocks when a CGNS database is closed and then reopened. It also verifies that all expected zones (blocks) exist on the database. Discovered by SPARC team. Verified that fix works for the issue that they reported. Developing a test to make this continues to work.