[turbofan] Drop V8_TURBOFAN_BACKEND and V8_TURBOFAN_TARGET defines.

src/compiler/pipeline.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_PIPELINE_H_
 #define V8_COMPILER_PIPELINE_H_
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 // Do not include anything from src/compiler here!
 #include "src/compiler.h"
@@ skipping 28 matching lines @@
   static Handle<Code> GenerateCodeForTesting(Isolate* isolate,
                                              CallDescriptor* call_descriptor,
                                              Graph* graph,
                                              Schedule* schedule = nullptr);
 
   // Run just the register allocator phases.
   static bool AllocateRegistersForTesting(const RegisterConfiguration* config,
                                           InstructionSequence* sequence,
                                           bool run_verifier);
 
-  static inline bool SupportedBackend() { return V8_TURBOFAN_BACKEND != 0; }
-  static inline bool SupportedTarget() { return V8_TURBOFAN_TARGET != 0; }
-
  private:
   static Handle<Code> GenerateCodeForTesting(CompilationInfo* info,
                                              CallDescriptor* call_descriptor,
                                              Graph* graph, Schedule* schedule);
 
   CompilationInfo* info_;
   PipelineData* data_;
 
   // Helpers for executing pipeline phases.
   template <typename Phase>
   void Run();
   template <typename Phase, typename Arg0>
   void Run(Arg0 arg_0);
 
   CompilationInfo* info() const { return info_; }
   Isolate* isolate() { return info_->isolate(); }
 
   void BeginPhaseKind(const char* phase_kind);
   void RunPrintAndVerify(const char* phase, bool untyped = false);
   Handle<Code> ScheduleAndGenerateCode(CallDescriptor* call_descriptor);
   void AllocateRegisters(const RegisterConfiguration* config,
                          bool run_verifier);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_PIPELINE_H_