Removed warnings from test suite


mysql-test/r/ctype_utf8.result:
  Update results after fix of return argument from date_format()
mysql-test/r/date_formats.result:
  Remove unnecessary warnings
mysql-test/r/type_decimal.result:
  Remove unnecessary warnings
mysql-test/r/warnings.result:
  Remove unnecessary warnings
mysql-test/t/ctype_utf8.test:
  Fixed test
mysql-test/t/date_formats.test:
  Remove unnecessary warnings
mysql-test/t/type_decimal.test:
  Remove unnecessary warnings
mysql-test/t/warnings.test:
  Remove unnecessary warnings
sql/field.cc:
  Optimize
sql/item_timefunc.cc:
  Ensure that result from date_format() is binary
strings/ctype-simple.c:
  Better names for arguments