Revert "[compiler] Ship Ignition for all TurboFan code."

src/api.cc

 // Copyright 2012 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/api.h"
 
 #include <string.h>  // For memcpy, strlen.
 #ifdef V8_USE_ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif  // V8_USE_ADDRESS_SANITIZER
@@ skipping 2240 matching lines @@
   }
   script->set_origin_options(origin.Options());
   if (!origin.SourceMapUrl().IsEmpty()) {
     script->set_source_mapping_url(
         *Utils::OpenHandle(*(origin.SourceMapUrl())));
   }
 
   source->info->set_script(script);
 
   {
-    // Create a canonical handle scope for compiling Ignition bytecode. This is
+    // Create a canonical handle scope if compiling ignition bytecode. This is
     // required by the constant array builder to de-duplicate objects without
     // dereferencing handles.
-    i::CanonicalHandleScope canonical(isolate);
+    std::unique_ptr<i::CanonicalHandleScope> canonical;
+    if (i::FLAG_ignition) canonical.reset(new i::CanonicalHandleScope(isolate));
 
     // Do the parsing tasks which need to be done on the main thread. This will
     // also handle parse errors.
     source->parser->Internalize(isolate, script,
                                 source->info->literal() == nullptr);
   }
   source->parser->HandleSourceURLComments(isolate, script);
 
   i::Handle<i::SharedFunctionInfo> result;
   if (source->info->literal() != nullptr) {
@@ skipping 7216 matching lines @@
   Address callback_address =
       reinterpret_cast<Address>(reinterpret_cast<intptr_t>(callback));
   VMState<EXTERNAL> state(isolate);
   ExternalCallbackScope call_scope(isolate, callback_address);
   callback(info);
 }
 
 
 }  // namespace internal
 }  // namespace v8