The ornamental design for a rectangularcollapsibletable, as shown and described.
FIG. 1 is a top perspective view of the rectangular collapsible table;
FIG. 2 is a left side elevation view of the rectangular collapsible, wherein a right side elevation view (not shown) is identical to the left side elevation view;
FIG. 3 is a front elevation view of the rectangular collapsible table, wherein a rear elevation view (not shown) is identical to the front elevation view; and,
FIG. 4 is a bottom perspective view of the rectangular collapsible table.