added test case
ctype-utf8.c:
  bug#11754: SET NAMES utf8 followed by SELECT "A\\" LIKE "A\\" returns 0


strings/ctype-utf8.c:
  bug#11754: SET NAMES utf8 followed by SELECT "A\\" LIKE "A\\" returns 0
mysql-test/t/ctype_utf8.test:
  added test case
mysql-test/r/ctype_utf8.result:
  added test case