[turbofan] Enable deoptimization for non-asm.js TurboFan code.

test/cctest/test-serialize.cc

 // Copyright 2007-2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1526 matching lines @@
   }
   isolate2->Dispose();
 }
 
 
 TEST(SerializeInternalReference) {
 #if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_ARM64
   return;
 #endif
   // Disable experimental natives that are loaded after deserialization.
-  FLAG_turbo_deoptimization = false;
   FLAG_context_specialization = false;
   FLAG_always_opt = true;
   const char* flag = "--turbo-filter=foo";
   FlagList::SetFlagsFromString(flag, StrLength(flag));
 
   const char* source =
       "var foo = (function(stdlib, foreign, heap) {"
       "  function foo(i) {"
       "    i = i|0;"
       "    var j = 0;"
@@ skipping 49 matching lines @@
   isolate->Dispose();
 }
 
 
 TEST(SerializationMemoryStats) {
   FLAG_profile_deserialization = true;
   FLAG_always_opt = false;
   v8::StartupData blob = v8::V8::CreateSnapshotDataBlob();
   delete[] blob.data;
 }