Revert of Add script context with context-allocated "const this"

src/scopes.h

 // 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.
 
 #ifndef V8_SCOPES_H_
 #define V8_SCOPES_H_
 
 #include "src/ast.h"
 #include "src/pending-compilation-error-handler.h"
 #include "src/zone.h"
@@ skipping 337 matching lines @@
     DCHECK_NOT_NULL(receiver_);
     return receiver_;
   }
 
   Variable* LookupThis() { return Lookup(ast_value_factory_->this_string()); }
 
   // TODO(wingo): Add a GLOBAL_SCOPE scope type which will lexically allocate
   // "this" (and no other variable) on the native context.  Script scopes then
   // will not have a "this" declaration.
   bool has_this_declaration() const {
-    return (is_function_scope() && !is_arrow_scope()) || is_module_scope();
+    return (is_function_scope() && !is_arrow_scope()) || is_module_scope() ||
+           is_script_scope();
   }
 
   // The variable corresponding to the 'new.target' value.
   Variable* new_target_var() { return new_target_; }
 
   // The variable holding the function literal for named function
   // literals, or NULL.  Only valid for function scopes.
   VariableDeclaration* function() const {
     DCHECK(is_function_scope());
     return function_;
@@ skipping 396 matching lines @@
   PendingCompilationErrorHandler pending_error_handler_;
 
   // For tracking which classes are declared consecutively. Needed for strong
   // mode.
   int class_declaration_group_start_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCOPES_H_