fix waterch_test failed in windows (#18635)
fix waterch_test failed in windows (#18635)

* fix waterch_test failed in windows

* fix waterch_test failed in windows by filepath

* fix istio top path

smawson/istio,istio/istio,smawson/istio,smawson/istio,istio/istio,smawson/istio,smawson/istio,istio/istio,smawson/istio,istio/istio,istio/istio