Oh ... come one ! These "rumours" are as stupid as Mach 10 flying operational hypersonic bombers in PLAAF-service or litle green men on Mars.
Additionally such considerations that "China should build the F-23" directly implies that the CHinese Aviation Industry should "copy" again a design instead of being independent.
Yet one final thought to keep up the testbed/prototype argument albeit from a different point of view: There are and there have been numerous testbeds/prototypes for various projects ... the whole X-series comes into mind but also in the west, the VSTOL Kestrel (pre-Harrier), EAP (pre-Eurofighter) ... why aren't such projects - at least I don't know any - in China to explore some certain technologies or configurations ??
Just my 2 cents.
Deino