The ornamental design for a vaginaldilator, as shown and described.
FIG. 1 is a perspective view of a vaginal dilator showing my new design;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a left view thereof;
FIG. 5 is a right view thereof;
FIG. 6 is a rear view thereof; and,
FIG. 7 is a front view thereof.
The broken lines shown in the views are included for the purpose of illustrating portion of the vaginal dilator that form no part of the claimed design. In addition, the internal surfaces adjoining the broken lines form no part of the claimed design.