Fix test configuration to run RacyGitTests, and fix testRacyGitDetection

Fix test configuration to run RacyGitTests, and fix testRacyGitDetection

With the filename suffix "Tests", the module was not included in tests
when building with Maven, and without the @Test annotations the tests
didn't get executed under Eclipse or buck test.

testRacyGitDetection was failing because the index file did not exist.

Add the missing configuration, the missing annotations, and add a call
to reset() in testRacyGitDetection to force creation of the index file.

Change-Id: I29dd8f89c36fef4ab40bedce7f4a26bd9b2390e4
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>