The ornamental design for a handdryer, as shown and described.
FIG. 1 is a front view of a hand dryer showing our new design. The back of the hand dryer unit is unadorned and its design is disclaimed herein.
FIG. 2 is a front, right-side perspective view thereof.
FIG. 3 is a top view thereof; and,
FIG. 4 is a side view thereof.
The broken lines showing elements of the hand dryer in the above-described Figures are for illustrative purposes only and form no part of the claimed design.