Various IWYU fixes.

src/ast/ast.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_AST_AST_H_
 #define V8_AST_AST_H_
 
+#include "src/assembler.h"
 #include "src/ast/ast-types.h"
 #include "src/ast/ast-value-factory.h"
 #include "src/ast/modules.h"
 #include "src/ast/variables.h"
 #include "src/bailout-reason.h"
 #include "src/base/flags.h"
 #include "src/factory.h"
 #include "src/globals.h"
 #include "src/isolate.h"
 #include "src/list.h"
@@ skipping 3585 matching lines @@
                                     : NULL;                                   \
   }
 AST_NODE_LIST(DECLARE_NODE_FUNCTIONS)
 #undef DECLARE_NODE_FUNCTIONS
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_AST_H_