The ornamental design for a polearmsupport, as shown and described.
FIG. 1 is a perspective view of a pole arm support showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a perspective view of the pole arm support showing the pole arm support of FIG. 1 rotated 180 degrees with additional broken line environment; and,
FIG. 9 is a perspective view showing two of the pole arm supports of FIG. 1 with additional broken line environment.
The dash-dot broken lines depict the bounds of the claimed design and the areas shown within the dash-dot lines represent portions of the pole arm support that form no part of the claimed design.