Add GTS tests for TreeHugger presubmit

Goal is to cover the following two areas with
the additions of three classes of presubmit tests:
- decrypt 0-length CryptoInfo
  coverage by CtsMediaTestCases in av/drm/mediadrm/plugins
  coverage by exoplayer.gts.DashTest
  coverage by media.gts.WidevineGenericOpsTests

Bug: 152407075

Test: atest
Summary
-------
arm64-v8a CtsMediaTestCases: Passed: 18, Failed: 0, Ignored: 0, Assumption Failed: 0
arm64-v8a GtsExoPlayerTestCases: Passed: 1, Failed: 0, Ignored: 0, Assumption Failed: 0
arm64-v8a GtsMediaTestCases: Passed: 2, Failed: 0, Ignored: 0, Assumption Failed: 0

Change-Id: Ic10759d2e61db3935420e7b7b12f5c15e9a28012
Merged-In: Ic10759d2e61db3935420e7b7b12f5c15e9a28012