Merge changes from topic "dscp_policies"

* changes:
  Don't enable DscpPolicyTracker on pre-T devices.
  Allow service JNI in FrameworksNetIntegrationTests.
  Don't manually load the JNI library in DscpPolicyTracker.
  Process DSCP QoS events for policies
  Allow using BpfMap and TcUtils in unit tests.