Problem: Various inconsistencies in test files.
Solution: Add modelines where they were missing. Use Check commands instead
of silently skipping over tests. Adjust indents and comments.
(Ken Takata, closes#6695)
Problem: Using the system default encoding makes tests unpredictable.
Solution: Always use utf-8 or latin1 in the new style tests. Remove setting
encoding and scriptencoding where it is not needed.
Problem: strcharpart() does not work properly with some multi-byte
characters.
Solution: Use mb_cptr2len() instead of mb_char2len(). (Hirohito Higashi)
