[Refactoring] ParamXXX::fp
Improve overloadApply for integrated function/template overloads
Use overloadApply for template overload set iteration
[Refactoring] Remove unused td_ambig
[Refactoring] Prepare merging
Copy ParamFuncRes::fp to ParamDeduce::fp
Merge functionResolve and templateResolve
Merge pull request #2401 from 9rnsr/refactor_overload

[Refactoring] Improve overload iteration and IFTI processing