[proxies] Use IsRevoked where possible, remove has_handler.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index 578ca4e877f25e1af709fbd5d0cb94c13c506324..c112156304b3b444e72176995b7cf41aac4ba6c9 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -9497,11 +9497,9 @@ class JSProxy: public JSReceiver {
 
   static MaybeHandle<Context> GetFunctionRealm(Handle<JSProxy> proxy);
 
-  inline bool has_handler();
-
   DECLARE_CAST(JSProxy)
 
-  static bool IsRevoked(Handle<JSProxy> proxy);
+  bool IsRevoked();
 
   // ES6 9.5.1
   static MaybeHandle<Object> GetPrototype(Handle<JSProxy> receiver);