vtkIOSSReader: sync format across ranks.

vtkIOSSReader was not syncing format type across ranks during
RequestInformation. That resulted in the format not being set when
reading block metadata causing the metadata to not be read on satellite
ranks even for CGNS. This was manifesting as paraview/paraview#20934.

Fixed that.

IO/IOSS/vtkIOSSReader.cxx

@@ -872,6 +872,11 @@ bool vtkIOSSReader::vtkInternals::UpdateTimeInformation(vtkIOSSReader* self)
     {
       dbase_times.clear();
     }
+
+    // this is a good place for us to sync up format too.
+    int iFormat = static_cast<int>(this->Format);
+    controller->Broadcast(&iFormat, 1, 0);
+    this->Format = static_cast<vtkIOSSUtilities::DatabaseFormatType>(iFormat);
   }
 
   // Fillup TimestepValues for ease of use later.
@@ -906,6 +911,9 @@ bool vtkIOSSReader::vtkInternals::UpdateEntityAndFieldSelections(vtkIOSSReader*
   std::array<std::set<std::string>, vtkIOSSReader::NUMBER_OF_ENTITY_TYPES> field_names;
   std::set<vtkIOSSUtilities::EntityNameType> bc_names;
 
+  // format should have been set (and synced) across all ranks by now.
+  assert(this->Format != vtkIOSSUtilities::UNKNOWN);
+
   // When each rank is reading multiple files, reading all those files for
   // gathering meta-data can be slow. However, with CGNS, that is required
   // since the file doesn't have information about all blocks in all files.