clean up unused includes and member variables

- Remove unused `#include "odb/PtrSetMap.h"` from Opendp.h.
- Remove unused `ordered_nets_` member variable from GlobalRouter.
- Remove unused standard library includes (<map>, <variant>, <vector>, <string>) from 3dblox.cpp and dbModNet.cpp.

Signed-off-by: Drew Lewis <cannada@google.com>

Author: calewis

src/dpl/include/dpl/Opendp.h

@@ -24,7 +24,6 @@
 #include "utl/Logger.h"
 // NOLINTNEXTLINE
 #include "boost/geometry/strategies/strategies.hpp"  // Required implictly by rtree
-#include "odb/PtrSetMap.h"
 #include "odb/db.h"
 #include "odb/dbTypes.h"
 #include "odb/geom.h"

src/grt/include/grt/GlobalRouter.h

@@ -529,7 +529,6 @@ class GlobalRouter
   NetRouteMap routes_;
   NetRouteMap partial_routes_;
 
-  std::vector<odb::dbNet*> ordered_nets_;
   odb::PtrMap<odb::dbNet, Net*> db_net_map_;
   Grid* grid_;
   std::map<int, odb::dbTechLayer*> routing_layers_;

src/odb/src/3dblox/3dblox.cpp

@@ -7,15 +7,12 @@
 #include <cstddef>
 #include <filesystem>
 #include <fstream>
-#include <map>
 #include <memory>
 #include <set>
 #include <sstream>
 #include <string>
 #include <unordered_set>
 #include <utility>
-#include <variant>
-#include <vector>
 
 #include "bmapParser.h"
 #include "bmapWriter.h"

src/odb/src/db/dbModNet.cpp

@@ -24,7 +24,6 @@
 #include <cstdint>
 #include <cstring>
 #include <iterator>
-#include <string>
 #include <string_view>
 #include <vector>