Fixes for LCG 99

Goes with: LHCb!2912 (merged), LHCb!2917 (merged), Rec!2342 (merged), and Phys!874 (merged)

1. Introduce nulltpr check before calling list() on pointer in Hlt/RecoConf/scripts/utils/Legend.py

2. Avoid double free of TF1 objects in python IPresolution plotting script. When calling fit on TH1 objects, the function is added to the histogram, thus automatically cleaned up by the histogram's destructor. One can check TH1::GetListOfFunctions to see all functions that are registered.

3. Patch some GaudiPython scripts such that the tests work. This should be considered temporary and is only implemented such that the tests work, and we can run them.

cc @rmatev @apearce since I think that point 3. is a bit connected to LBRTAPLAN-276. It really seems that the new cppyy changed quite a few things and probably broke more things than we are currently aware of... Given that a few simple things like TES.dump() were broken and not noticed until in Moore also has me questioning how much test coverage we have for GaudiPython (But to be discussed on the jira I guess. Just wanted to ping you so you know about this ;) )