simplify net-gateway-api install

- we can reuse net-istio's third_party istio install yaml
- use the gateway api crds in third_party - the prior download url didn't work

test/e2e-common.sh

@@ -210,7 +210,7 @@ function knative_setup() {
   fi
 
   # Download Istio YAMLs
-  if is_ingress_class istio; then
+  if is_ingress_class istio || is_ingress_class gateway-api; then
     stage_istio_head
 
     # Download istio resources we need for upgrade tests
@@ -219,18 +219,6 @@ function knative_setup() {
     fi
   fi
 
-  # Install gateway-api and istio. Gateway API CRD must be installed before Istio.
-  if is_ingress_class gateway-api; then
-    # TODO: Do not use fixed Gateway API version and Istio version.
-    kubectl apply -k 'github.com/kubernetes-sigs/gateway-api/config/crd?ref=v0.3.0'
-    export ISTIO_VERSION=1.11.4 && curl -sL https://istio.io/downloadIstioctl | sh -
-    if (( KIND )); then
-      $HOME/.istioctl/bin/istioctl install -y --set values.gateways.istio-ingressgateway.type=NodePort --set values.global.proxy.clusterDomain="${CLUSTER_DOMAIN}"
-    else
-      $HOME/.istioctl/bin/istioctl install -y --set values.global.proxy.clusterDomain="${CLUSTER_DOMAIN}"
-    fi
-  fi
-
   stage_test_resources
 
   install "${INSTALL_SERVING_VERSION}" "${INSTALL_ISTIO_VERSION}"
@@ -339,12 +327,6 @@ function install() {
     # kubectl -n ${SYSTEM_NAMESPACE} delete leases --all
     wait_for_leader_controller || return 1
   fi
-
-  # Due to https://github.com/vmware-tanzu/carvel-kapp/issues/381, deploy svc by kubectl instead of kapp.
-  if is_ingress_class gateway-api; then
-    kubectl delete -f ${REPO_ROOT_DIR}/third_party/gateway-api-latest/istio-gateway.yaml
-    kubectl apply -f ${REPO_ROOT_DIR}/third_party/gateway-api-latest/istio-gateway.yaml
-  fi
 }
 
 # Check if we should use --resolvabledomain.  In case the ingress only has