Fix uses of int instead of EMACS_INT in intervals.c.

Fix uses of int instead of EMACS_INT in intervals.c.

 intervals.c (traverse_intervals, rotate_right, rotate_left)
 (balance_an_interval, split_interval_right, split_interval_left)
 (find_interval, next_interval, update_interval)
 (adjust_intervals_for_insertion, delete_node, delete_interval)
 (interval_deletion_adjustment, adjust_intervals_for_deletion)
 (offset_intervals, merge_interval_right, merge_interval_left)
 (graft_intervals_into_buffer, adjust_for_invis_intang)
 (move_if_not_intangible, get_local_map, copy_intervals)
 (copy_intervals_to_string, compare_string_intervals)
 (set_intervals_multibyte_1): Use EMACS_INT for buffer positions
 and EMACS_UINT for interval tree size.
 intervals.h (traverse_intervals, split_interval_right)
 (split_interval_left, find_interval, offset_intervals)
 (graft_intervals_into_buffer, copy_intervals)
 (copy_intervals_to_string, move_if_not_intangible, get_local_map)
 (update_interval): Adjust prototypes.