glretrace: Plug AMD_perfmon to the collection.
glretrace: Plug AMD_perfmon to the collection.

Add an entry in glretrace::getBackend().
Pass current context to AMD_perfmon constructor, so that it can check if
corresponding GL extension is supported.

trtt/apitrace,schulmar/apitrace,apitrace/apitrace,schulmar/apitrace,EoD/apitrace,trtt/apitrace,EoD/apitrace,apitrace/apitrace,trtt/apitrace,schulmar/apitrace,trtt/apitrace,apitrace/apitrace,schulmar/apitrace,trtt/apitrace,apitrace/apitrace,EoD/apitrace,EoD/apitrace,schulmar/apitrace,EoD/apitrace