[turbofan] Drop V8_TURBOFAN_BACKEND and V8_TURBOFAN_TARGET defines.

test/cctest/compiler/test-branch-combine.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "test/cctest/cctest.h"
 #include "test/cctest/compiler/codegen-tester.h"
 #include "test/cctest/compiler/value-helper.h"
 
-#if V8_TURBOFAN_TARGET
-
 using namespace v8::internal;
 using namespace v8::internal::compiler;
 
 typedef RawMachineAssembler::Label MLabel;
 
 static IrOpcode::Value int32cmp_opcodes[] = {
     IrOpcode::kWord32Equal, IrOpcode::kInt32LessThan,
     IrOpcode::kInt32LessThanOrEqual, IrOpcode::kUint32LessThan,
     IrOpcode::kUint32LessThanOrEqual};
 
@@ skipping 429 matching lines @@
               invert ? (cmp.Float64Compare(input_a, input_b) ? ne_constant
                                                              : eq_constant)
                      : (cmp.Float64Compare(input_a, input_b) ? eq_constant
                                                              : ne_constant);
           CHECK_EQ(expected, m.Call());
         }
       }
     }
   }
 }
-#endif  // V8_TURBOFAN_TARGET