The ornamental design for a double layer athletic shorts, as shown and described.
FIG. 1 is a front perspective view of the double layer shorts showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is a front elevation view of the present embodiment in use.
The long dashed lines depict stitching and form part of the claimed design. The short broken lines depict portions of the double layer athletic shorts and form no part of the claimed design.