trace: Move parameter unwraping out of traceFunctionImplBody/implementWrapperInterfaceMethodBody.
trace: Move parameter unwraping out of traceFunctionImplBody/implementWrapperInterfaceMethodBody.

Should make no difference by itself, but it is more useful like that, and
is needed by follow-on changes.

joshua5201/apitrace,joshua5201/apitrace,trtt/apitrace,schulmar/apitrace,tuanthng/apitrace,surround-io/apitrace,tuanthng/apitrace,EoD/apitrace,tuanthng/apitrace,swq0553/apitrace,schulmar/apitrace,surround-io/apitrace,apitrace/apitrace,apitrace/apitrace,apitrace/apitrace,surround-io/apitrace,surround-io/apitrace,EoD/apitrace,swq0553/apitrace,tuanthng/apitrace,EoD/apitrace,trtt/apitrace,tuanthng/apitrace,trtt/apitrace,joshua5201/apitrace,apitrace/apitrace,trtt/apitrace,surround-io/apitrace,swq0553/apitrace,EoD/apitrace,schulmar/apitrace,trtt/apitrace,swq0553/apitrace,EoD/apitrace,joshua5201/apitrace,joshua5201/apitrace,swq0553/apitrace,schulmar/apitrace,schulmar/apitrace