fix(java): add -ntp flag to native image testing command (#1299) (#775)

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
-  digest: sha256:4e961d006ec9e44501273788f3cbe1e060c4666742ba190f60d6a05bcdf3ac8f
   image: gcr.io/cloud-devrel-public-resources/owlbot-java:latest
+  digest: sha256:a4d7b2cfc6a9d6b378a6b2458740eae15fcab28854bd23dad3a15102d2e47c87

.kokoro/build.sh

@@ -71,7 +71,7 @@ integration)
     ;;
 graalvm)
     # Run Unit and Integration Tests with Native Image
-    mvn test -Pnative -Penable-integration-tests
+    mvn -ntp -Pnative -Penable-integration-tests test
     RETURN_CODE=$?
     ;;
 samples)