The ornamental design for a non-spill container, as shown and described.
FIG. 1 is a perspective view of a non-spill container;
FIG. 2 is a front view of the non-spill container, the rear view (omitted) being a mirror image thereof;
FIG. 3 is a right side view of the non-spill container, the left side view (omitted) being a mirror image thereof;
FIG. 4 is a top view of the non-spill container;
FIG. 5 is a bottom view of the non-spill container; and,
FIG. 6 is a right side view of the non-spill container with the lid removed from the bowl.
The broken lines in the figures showing portions of the non-spill container in FIGS. 1-6 are for illustrative purposes only and form no part of the claimed design.