Two character mappings were way off (backtick and tilde were "E"
and "Y"!), and three others were slightly rotated.  The first 
would cause collisions, and the latter was probably benign.

Now, assign the character mappings exactly to their normal values.


sql/share/charsets/ascii.xml:
  Change the character mapping for 
   "`" to "`" (was "E") and 
   "[" to "[" (was "\") and 
   "\" to "\" (was "]") and
   "]" to "]" (was "[") and 
   "~" to "~" (was "Y").
strings/ctype-extra.c:
  Generated from charsets directory.
mysql-test/r/ctype_ascii.result:
  Add new test file.
  
  Test all combinations of printable letter comparisons for 
  similarity.
mysql-test/t/ctype_ascii.test:
  Add new test file.
  
  Test all combinations of printable letter comparisons for 
  similarity.