Why do you introduce a discussion of wind shear when you previously were arguing the case of steady wind and I specifically stated "uniform airmass"?
How about keeping it simple to start with.
Case 1. Aircraft makes continuous circles at constant altitude with no change in thrust. The aircraft is in a completely uniform airmass that has no motion relative to the surface of the earth. What happens to indicated airspeed during the turn?
Case 2. Aircraft makes continuous circles at constant altitude with no change in thrust. The aircraft is in a completely uniform airmass that is moving with contant speed and direction relative to the surface of the earth. What happens to indicated airspeed during the turn?