The ornamental design for a racetrackmat, as shown and described.
The sole FIGURE is a top view of a racetrack mat showing my new design.
The bottom and side of the racetrack mat are not claimed.
The broken line drawing on the racetrack represents road markings and is part of the claimed design; however, the 3 broken line areas in each corner of the racetrack are for environmentally purposes only and forms no part of the claim design also, the broken line surrounding the design indicates the boundary of the claimed design and forms no part of the claimed design.