[clang][dataflow] Remove deprecated `transfer(const Stmt *, ...)` API.

clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h

 #define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_DATAFLOWANALYSIS_H
 
 #include <iterator>
 #include <type_traits>
 #include <utility>
 #include <vector>
 
 #include "clang/AST/ASTContext.h"
-#include "clang/AST/Stmt.h"
 #include "clang/Analysis/CFG.h"
 #include "clang/Analysis/FlowSensitive/ControlFlowContext.h"
 #include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"
 #include "clang/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.h"
 #include "llvm/ADT/Any.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Error.h"
 
 namespace clang {
 namespace dataflow {
 
-template <typename AnalysisT, typename LatticeT, typename InputT,
-          typename = std::void_t<>>
-struct HasTransferFor : std::false_type {};
-
-template <typename AnalysisT, typename LatticeT, typename InputT>
-struct HasTransferFor<
-    AnalysisT, LatticeT, InputT,
-    std::void_t<decltype(std::declval<AnalysisT>().transfer(
-        std::declval<const InputT *>(), std::declval<LatticeT &>(),
-        std::declval<Environment &>()))>> : std::true_type {};
-
 /// Base class template for dataflow analyses built on a single lattice type.
 ///
 /// Requirements:
 ///
 ///  `Derived` must be derived from a specialization of this class template and
 ///  must provide the following public members:
 ///   * `LatticeT initialElement()` - returns a lattice element that models the
 ///     initial state of a basic block;
bool isEqualTypeErased(const TypeErasedLattice &E1,
     const Lattice &L1 = llvm::any_cast<const Lattice &>(E1.Value);
     const Lattice &L2 = llvm::any_cast<const Lattice &>(E2.Value);
     return L1 == L2;
   }
 
   void transferTypeErased(const CFGElement *Element, TypeErasedLattice &E,
                           Environment &Env) final {
     Lattice &L = llvm::any_cast<Lattice &>(E.Value);
-    if constexpr (HasTransferFor<Derived, LatticeT, CFGElement>::value) {
-      static_cast<Derived *>(this)->transfer(Element, L, Env);
-    }
 
-    // FIXME: Remove after users have been updated to implement `transfer` on
-    // `CFGElement`.
-    if constexpr (HasTransferFor<Derived, LatticeT, Stmt>::value) {
-      if (auto Stmt = Element->getAs<CFGStmt>()) {
-        static_cast<Derived *>(this)->transfer(Stmt->getStmt(), L, Env);
-      }
-    }
-  }
-
 private:
   ASTContext &Context;
 };
 
 // Model of the program at a given program point.
 template <typename LatticeT> struct DataflowAnalysisState {
   // Model of a program property.
   LatticeT Lattice;