Drop explicite SSBO bindings and add extensions that enable barriers on GL hosts
Two tests have regressed on GL hosts that pass on GLES hosts, and are fixed by this (See #201 (closed)). It seems that the guest already takes care of the correct bindings and we only make things worse by trying to apply new bindings.
I've also tested this patch running the GL-CTS GL43 subset via vtest on an Intel host, and there I didn't seen any regressions between emitting.
Edited by Gert Wollny