[turbofan] Drop V8_TURBOFAN_BACKEND and V8_TURBOFAN_TARGET defines.

test/cctest/compiler/test-run-inlining.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/compiler/function-tester.h"
 
-#if V8_TURBOFAN_TARGET
-
 using namespace v8::internal;
 using namespace v8::internal::compiler;
 
 namespace {
 
 // Helper to determine inline count via JavaScriptFrame::GetFunctions.
 // Note that a count of 1 indicates that no inlining has occured.
 void AssertInlineCount(const v8::FunctionCallbackInfo<v8::Value>& args) {
   StackTraceFrameIterator it(CcTest::i_isolate());
   int frames_seen = 0;
@@ skipping 546 matching lines @@
       "    if (x == 1) return bar(42);"
       "    return x;"
       "  }"
       "  return foo;"
       "})();",
       kInlineFlags);
 
   InstallAssertInlineCountHelper(CcTest::isolate());
   T.CheckCall(T.Val(42), T.Val(1));
 }
-
-#endif  // V8_TURBOFAN_TARGET