Fix for extra zero in exponent of double values on windows.


client/mysqltest.c:
  Write new function 'append_field' which takes care of appending one field to the dynamic string.
  Use function 'append_field' from both ps and normal execution
  Add hack to 'append_field' that removes the extra '0' in exponent for double values on Windows.
mysql-test/r/type_float.result:
  One zero too much was removed( I think )
mysql-test/t/insert.test:
  Remove the "replace_result" for extra zero in  exponent
mysql-test/t/type_float.test:
  Remove the "replace_result" for extra zero in  exponent
mysql-test/t/variables.test:
  Remove the "replace_result" for extra zero in  exponent