Update package name change.

As part of bug b/171226061 to separate DRM test
classes to enable better tracking of test failures
through the OWNERs files.

The drm tests now reside in android.mediadrm.cts package.
The following tests are moved:
  MediaDrmClearkeyTest, MediaDrmMetricsTest and
  NativeMediaDrmClearkeyTest

Test: atest --test-mapping

Bug: 190625926
Change-Id: Ic5778d2989a0a1583cfd36a5cc68c50ec404f7ae