Fix bug #9221 with memory leak in bidi display.

Fix bug #9221 with memory leak in bidi display.
Add code to monitor memory allocation for bidi cache shelving.

 src/xdisp.c (display_line): Release buffer allocated for shelved bidi
 cache.
 src/bidi.c (bidi_shelve_cache, bidi_unshelve_cache): Track total
 amount allocated this far in `bidi_cache_total_alloc'.
 (bidi_unshelve_cache): Accept an additional argument JUST_FREE; if
 non-zero, only free the data buffer without restoring the cache
 contents.  All callers changed.
 src/dispextern.h (bidi_unshelve_cache): Update prototype.
 src/xdisp.c (SAVE_IT, pos_visible_p, move_it_in_display_line_to)
 (move_it_in_display_line, move_it_to)
 (move_it_vertically_backward, move_it_by_lines): Replace the call
 to xfree to an equivalent call to bidi_unshelve_cache.
 (move_it_in_display_line_to): Fix logic of returning
 MOVE_POS_MATCH_OR_ZV in the bidi case.