authfs: Re-enable the build of device unit test

The build rule was removed due to broken presumit on Tree Hugger. This
change only re-enable the build rule without adding TEST_MAPPING.

Test: atest
Bug: 173507504
Change-Id: Iadc8cd6074140185ecd3ae3db017c7f1573f5f4e
1 file changed
tree: 980e60f1162686f418f067dd3a1917f720ff6684
  1. apex/
  2. authfs/
  3. docs/
  4. tests/
  5. .clang-format
  6. PREUPLOAD.cfg