Delete some now-unused functions

These were used for converting to the file format where ObjKeys were derived
from primary keys.

src/realm/table.cpp

@@ -1577,16 +1577,6 @@ uint64_t Table::allocate_sequence_number()
     return sn;
 }
 
-void Table::set_sequence_number(uint64_t seq)
-{
-    m_top.set(top_position_for_sequence_number, RefOrTagged::make_tagged(seq));
-}
-
-void Table::set_collision_map(ref_type ref)
-{
-    m_top.set(top_position_for_collision_map, RefOrTagged::make_ref(ref));
-}
-
 void Table::set_col_key_sequence_number(uint64_t seq)
 {
     m_top.set(top_position_for_column_key, RefOrTagged::make_tagged(seq));

src/realm/table.hpp

@@ -415,9 +415,6 @@ class Table {
     TableKey get_key() const noexcept;
 
     uint64_t allocate_sequence_number();
-    // Used by upgrade
-    void set_sequence_number(uint64_t seq);
-    void set_collision_map(ref_type ref);
     // Used for testing purposes.
     void set_col_key_sequence_number(uint64_t seq);