Add node support

Author: sergiitk

.kokoro/psm_interop_kokoro_lib.sh

@@ -331,6 +331,9 @@ psm::run::test() {
   # Some test suites have canonical server image configured in the flagfiles.
   if [[ -z "${SERVER_IMAGE_USE_CANONICAL}" ]]; then
     PSM_TEST_FLAGS+=("--server_image=${SERVER_IMAGE_NAME}:${GIT_COMMIT}")
+  elif [[ "${GRPC_LANGUAGE}" == "node"  ]]; then
+    # TODO(b/261911148): To be replaced with --server_image_use_canonical when implemented.
+    PSM_TEST_FLAGS+=("--server_image=us-docker.pkg.dev/grpc-testing/psm-interop/java-server:canonical")
   fi
 
   # So far, only LB test uses secondary GKE cluster.
@@ -380,6 +383,11 @@ psm::setup::docker_image_names() {
       CLIENT_IMAGE_NAME="${DOCKER_REGISTRY}/grpc-testing/psm-interop/${GRPC_LANGUAGE}-client"
       SERVER_IMAGE_NAME="${DOCKER_REGISTRY}/grpc-testing/psm-interop/${GRPC_LANGUAGE}-server"
       ;;
+    node)
+      CLIENT_IMAGE_NAME="${DOCKER_REGISTRY}/grpc-testing/psm-interop/${GRPC_LANGUAGE}-client"
+      SERVER_IMAGE_NAME=""
+      SERVER_IMAGE_USE_CANONICAL="1"
+      ;;
     *)
       psm::tools::log "Unknown Language: ${1}"
       exit 1