VtsHalDrm: run tests in single shard

Currently drm cert provisioning is performed as an indivdual test case.
Other tests (e.g. decrypt tests) have dependency on drm cert
provisioning.

Bug: 165493235
Test: VtsHalDrmV1_0TargetTest
Test: VtsHalDrmV1_1TargetTest
Test: VtsHalDrmV1_2TargetTest
Test: VtsHalDrmV1_3TargetTest
Change-Id: I7aad35747997e6ce5b06919344475e0f2754cd15