[turbofan] Drop V8_TURBOFAN_BACKEND and V8_TURBOFAN_TARGET defines.

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 3f47e71bdf2ac54d52663444d183f1b8994248a6..ecceb81943a97eec2f772c80754cc5c54d067ee5 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -21178,11 +21178,7 @@ TEST(TurboAsmDisablesNeuter) {
   v8::V8::Initialize();
   v8::HandleScope scope(CcTest::isolate());
   LocalContext context;
-#if V8_TURBOFAN_TARGET
   bool should_be_neuterable = !i::FLAG_turbo_asm;
-#else
-  bool should_be_neuterable = true;
-#endif
   const char* load =
       "function Module(stdlib, foreign, heap) {"
       "  'use asm';"