examples: add VRP runtime validation to verify_examples. (#14099)

This is a regression test to cover the issue underlying
#14066.

Risk level: Low
Testing: Validating manually verify.sh passes, CI.

Signed-off-by: Harvey Tuch <htuch@google.com>

examples/vrp-litmus/Dockerfile-vrp

@@ -0,0 +1 @@
+FROM envoyproxy/envoy-google-vrp-dev:latest

examples/vrp-litmus/README.md

@@ -0,0 +1,3 @@
+Simple litmus test to verify the VRP image in CI. For more details on VRP,
+please see
+https://www.envoyproxy.io/docs/envoy/latest/intro/arch_overview/security/google_vrp.

examples/vrp-litmus/docker-compose.yaml

@@ -0,0 +1,17 @@
+version: "3.7"
+services:
+
+  vrp:
+    build:
+      context: .
+      dockerfile: Dockerfile-vrp
+    environment:
+      ENVOY_EDGE_EXTRA_ARGS: ""
+      ENVOY_ORIGIN_EXTRA_ARGS: ""
+    networks:
+      - envoymesh
+    ports:
+      - "10000:10000"
+
+networks:
+  envoymesh: {}

examples/vrp-litmus/verify.sh

@@ -0,0 +1,14 @@
+#!/bin/bash -e
+
+export NAME=vrp-litmus
+export DELAY=10
+
+# shellcheck source=examples/verify-common.sh
+. "$(dirname "${BASH_SOURCE[0]}")/../verify-common.sh"
+
+
+run_log "Test proxy"
+responds_with \
+    normal \
+    https://localhost:10000/content \
+    -k