selftests: tc-testing: add action offload selftest for action and filter

Add selftest cases in action police with skip_hw.
Add selftest case to validate flags of filter and action.
These tests depend on corresponding iproute2 command support.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>