Add lazy evaluation for impactconditionbranch nodes

[mijuku233]

I think it would be better to just add lazy evaluation to impactconditionbranch and then revert impactconditionbranchselmode.

An update disabled selmode for impactconditionbranchselmode, but sometimes selmode is still a useful option and disabling it breaks a lot of workflows.

[mijuku233]

Some of my workflows that used impactconditionbranchselmode have been broken, and others have had issues with the change to impactconditionbranchselmode. #714