Remove deprecated symbol_exprt and decorated_symbol_exprt constructors

These have been deprecated since 21 Sept 2018.

Author: tautschnig

src/util/std_expr.h

@@ -92,18 +92,6 @@ class ternary_exprt : public exprt
 class symbol_exprt : public nullary_exprt
 {
 public:
-  DEPRECATED("use symbol_exprt(identifier, type) instead")
-  symbol_exprt() : nullary_exprt(ID_symbol)
-  {
-  }
-
-  /// \param identifier: Name of symbol
-  DEPRECATED("use symbol_exprt(identifier, type) instead")
-  explicit symbol_exprt(const irep_idt &identifier) : nullary_exprt(ID_symbol)
-  {
-    set_identifier(identifier);
-  }
-
   /// \param type: Type of symbol
   explicit symbol_exprt(const typet &type) : nullary_exprt(ID_symbol, type)
   {
@@ -142,25 +130,6 @@ class symbol_exprt : public nullary_exprt
 class decorated_symbol_exprt:public symbol_exprt
 {
 public:
-  DEPRECATED("use decorated_symbol_exprt(identifier, type) instead")
-  decorated_symbol_exprt()
-  {
-  }
-
-  /// \param identifier: Name of symbol
-  DEPRECATED("use decorated_symbol_exprt(identifier, type) instead")
-  explicit decorated_symbol_exprt(const irep_idt &identifier):
-    symbol_exprt(identifier)
-  {
-  }
-
-  /// \param type: Type of symbol
-  DEPRECATED("use decorated_symbol_exprt(identifier, type) instead")
-  explicit decorated_symbol_exprt(const typet &type):
-    symbol_exprt(type)
-  {
-  }
-
   /// \param identifier: Name of symbol
   /// \param type: Type of symbol
   decorated_symbol_exprt(