Move CacheDataSourceContractTest to c.g.a.exoplayer2.upstream.cache

This is the package that CacheDataSource and CacheDataSourceTest(2) are
in.

PiperOrigin-RevId: 380156879

library/core/src/test/java/com/google/android/exoplayer2/upstream/CacheDataSourceContractTest.java → library/core/src/test/java/com/google/android/exoplayer2/upstream/cache/CacheDataSourceContractTest.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.google.android.exoplayer2.upstream;
+package com.google.android.exoplayer2.upstream.cache;
 
 import android.net.Uri;
 import androidx.annotation.Nullable;
@@ -23,9 +23,7 @@ import com.google.android.exoplayer2.testutil.DataSourceContractTest;
 import com.google.android.exoplayer2.testutil.FakeDataSet;
 import com.google.android.exoplayer2.testutil.FakeDataSource;
 import com.google.android.exoplayer2.testutil.TestUtil;
-import com.google.android.exoplayer2.upstream.cache.CacheDataSource;
-import com.google.android.exoplayer2.upstream.cache.NoOpCacheEvictor;
-import com.google.android.exoplayer2.upstream.cache.SimpleCache;
+import com.google.android.exoplayer2.upstream.DataSource;
 import com.google.android.exoplayer2.util.Util;
 import com.google.common.collect.ImmutableList;
 import java.io.File;