fails randomly.

The problem is that the test was affected by other running
test-suites on the same box. The fix affects the test only,
no code touched.


mysql-test/r/im_instance_conf.result:
  Updated result file.
mysql-test/t/disabled.def:
  Enable IM tests.
mysql-test/t/im_instance_conf.imtest:
  Modify the test so that it does not depend on running
  test-suites on the same box.