Re-introduce ImportDeclaration to the parser

src/runtime/runtime-scopes.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 "src/accessors.h"
 #include "src/arguments.h"
 #include "src/frames-inl.h"
 #include "src/runtime/runtime-utils.h"
@@ skipping 772 matching lines @@
     Handle<JSModule> module(context->module());
 
     for (int j = 0; j < description->length(); ++j) {
       Handle<String> name(description->name(j));
       VariableMode mode = description->mode(j);
       int index = description->index(j);
       switch (mode) {
         case VAR:
         case LET:
         case CONST:
-        case CONST_LEGACY: {
+        case CONST_LEGACY:
+        case IMPORT: {
           PropertyAttributes attr =
               IsImmutableVariableMode(mode) ? FROZEN : SEALED;
           Handle<AccessorInfo> info =
               Accessors::MakeModuleExport(name, index, attr);
           Handle<Object> result =
               JSObject::SetAccessor(module, info).ToHandleChecked();
           DCHECK(!result->IsUndefined());
           USE(result);
           break;
         }
@@ skipping 309 matching lines @@
   return Smi::FromInt(frame->GetArgumentsLength());
 }
 
 
 RUNTIME_FUNCTION(RuntimeReference_Arguments) {
   SealHandleScope shs(isolate);
   return __RT_impl_Runtime_GetArgumentsProperty(args, isolate);
 }
 }
 }  // namespace v8::internal