LibJS: Remove unnecessary AST.h include in a handful of cpp files

Author: https://github.com/awesomekling
Commit: 3f1ffc2b94
Pull-request: https://github.com/SerenityOS/serenity/pull/16153
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibJS/Runtime/Reference.cpp

@@ -4,7 +4,6 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <LibJS/AST.h>
 #include <LibJS/Runtime/DeclarativeEnvironment.h>
 #include <LibJS/Runtime/Error.h>
 #include <LibJS/Runtime/GlobalObject.h>