SL-13826 Show result of "Find original" and "Show original" in Main Inventory floater and reset the filters to guarantee success

following promotion of DRTVWR-507

LLHUDObject has a lot of deriveds stored as LLPointer<LLHUDObject>, no-virtual destructor is unlikely to be cause of the crash, but might be related

# Conflicts:
#	indra/newview/llfloatermodelpreview.cpp

following promotion of DRTVWR-482

LLVOAvatars and derived classes appear to be stored as LLPointer<LLViewerObject> in a lot of cases, so non-virtual ~LLViewerObject() might be triggered by LLPointer and end up not cleaning sInstances in some cases (animeshes specific?), thus causing broken pointers in sInstances.