[REFACTOR][FFI] Phase out old VisitAttrs mechanism

This PR phases out the old VisitAttrs mechanism as we fully
transition to use the new reflection mechanism for attribute get
and object creation.

Author: tqchen

ffi/include/tvm/ffi/object.h

@@ -214,7 +214,6 @@ class Object {
   static constexpr int32_t _type_depth = 0;
   // extra fields used by plug-ins for attribute visiting
   // and structural information
-  static constexpr const bool _type_has_method_visit_attrs = true;
   static constexpr const bool _type_has_method_sequal_reduce = false;
   static constexpr const bool _type_has_method_shash_reduce = false;
   // The following functions are provided by macro

include/tvm/arith/int_solver.h

@@ -83,7 +83,6 @@ class IntGroupBoundsNode : public Object {
     hash_reduce(upper);
   }
 
-  static constexpr const bool _type_has_method_visit_attrs = false;
   static constexpr const bool _type_has_method_sequal_reduce = true;
   static constexpr const char* _type_key = "arith.IntGroupBounds";
   TVM_DECLARE_FINAL_OBJECT_INFO(IntGroupBoundsNode, Object);
@@ -174,7 +173,6 @@ class IntConstraintsNode : public Object {
     hash_reduce(relations);
   }
 
-  static constexpr const bool _type_has_method_visit_attrs = false;
   static constexpr const bool _type_has_method_sequal_reduce = true;
   static constexpr const char* _type_key = "arith.IntConstraints";
   TVM_DECLARE_FINAL_OBJECT_INFO(IntConstraintsNode, Object);
@@ -240,7 +238,6 @@ class IntConstraintsTransformNode : public Object {
     hash_reduce(dst_to_src);
   }
 
-  static constexpr const bool _type_has_method_visit_attrs = false;
   static constexpr const bool _type_has_method_sequal_reduce = true;
   static constexpr const char* _type_key = "arith.IntConstraintsTransform";
   TVM_DECLARE_FINAL_OBJECT_INFO(IntConstraintsTransformNode, Object);