Fix pos-visible-in-window-p under bidi redisplay.

Fix pos-visible-in-window-p under bidi redisplay.

 src/xdisp.c (move_it_in_display_line_to): Record the best matching
 position for TO_CHARPOS while scanning the line, and restore it on
 exit if none of the characters scanned was an exact match.  Fixes
 vertical-motion and pos-visible-in-window-p under bidi redisplay
 when exact match is impossible due to invisible text, and the
 lines are truncated.