Delete SearchServiceTest.java.

This PR removes a test that doesn't do anything useful at the moment. We already have a set of search tests written in Python:
- http://ci.openmicroscopy.org/view/5.1/job/OMERO-5.1-merge-integration-python/lastCompletedBuild/testReport/test.integration.clitest.test_search/TestSearch/,
- http://ci.openmicroscopy.org/view/5.1/job/OMERO-5.1-merge-integration-python/lastCompletedBuild/testReport/test.integration.test_search/TestSearch/

which are more useful than the empty classes removed in this PR.