Autotest: Fix unittest file names so they are ran.

The automatic test finding script does not find files of the form
*_unittests.py. These have been renamed to be *_unittest.py.

BUG=None
TEST=Ran test ./utils/unittests_suite.py with --debug flag and verified tests
were ran.

Change-Id: Idfc6ee90a19138d486e9167620d6e4df14b84c76
Reviewed-on: https://gerrit.chromium.org/gerrit/65270
Reviewed-by: Keyar Hood <keyar@chromium.org>
Tested-by: Keyar Hood <keyar@chromium.org>
Commit-Queue: Keyar Hood <keyar@chromium.org>
3 files changed