In SetFunc() instead of using the cling lookup helper directly,
use TClingInfo::GetMethodWithArgs() instead so that function
lookup is centralized and we can intercept it there to use
wrappers when necessary.  This has the nice side-effect of
centralizing the poffset processing as well.

Make sure we clear the cached argument list on call.


git-svn-id: https://root.cern.ch/svn/root/trunk@48417 27541ba8-7e3a-0410-8455-c3a389f83636
Make error handling the same as SetFunc().


git-svn-id: https://root.cern.ch/svn/root/trunk@48418 27541ba8-7e3a-0410-8455-c3a389f83636