RFR (S) 8062307: 'Reference handler' thread triggers assert w/ TraceThreadEvents

[David Holmes]

Bug: https://bugs.openjdk.java.net/browse/JDK-8062307

Webrev: http://cr.openjdk.java.net/~dholmes/8062307/webrev/

It turns out that the little known TraceThreadEvents logic has been 
broken since at least very early in JDK 5. A develop-only option it was 
intended to show when different Thread methods were called (the VM side 
of certain java.lang.Thread methods). While that sounds potentially 
useful for debugging it seems that in practice it is not - this has been 
broken for over 10 years with nobody noticing: it is unused. So rather 
than fix unused code it is proposed to simply delete it instead.

Thanks,
David