chore: No longer install cloud-sql-proxy in the test script since it should already be present in the image (#1548)

Author: dazuma

.kokoro/system_tests.sh

@@ -16,8 +16,5 @@ source $KOKORO_GFILE_DIR/secrets.sh
 # Move into the repo
 cd github/ruby-docs-samples/
 
-# Install tools
-gem install --no-document toys
-
 # Run the CI script
 toys kokoro-ci -v

.toys/kokoro-ci.rb

@@ -213,7 +213,6 @@ def start_app_engine_services
 #
 def start_cloud_sql_services
   if @products.include? "cloud-sql/mysql"
-    install_cloud_sql_proxy
     puts "Starting Cloud SQL Proxy for MySQL", :bold
     connection_name = assert_env "MYSQL_INSTANCE_CONNECTION_NAME"
     process = exec ["/bin/cloud_sql_proxy",
@@ -224,7 +223,6 @@ def start_cloud_sql_services
     @kill_on_cleanup << process
   end
   if @products.include? "cloud-sql/postgres"
-    install_cloud_sql_proxy
     puts "Starting Cloud SQL Proxy for Postgres", :bold
     connection_name = assert_env "POSTGRES_INSTANCE_CONNECTION_NAME"
     process = exec ["/bin/cloud_sql_proxy",
@@ -235,7 +233,6 @@ def start_cloud_sql_services
     @kill_on_cleanup << process
   end
   if @products.include? "cloud-sql/postgres"
-    install_cloud_sql_proxy
     puts "Starting Cloud SQL Proxy for SQL Server", :bold
     connection_name = assert_env "SQLSERVER_INSTANCE_CONNECTION_NAME"
     process = exec ["/bin/cloud_sql_proxy",
@@ -256,22 +253,6 @@ def start_memcached
   exec ["service", "memcached", "start"]
 end
 
-##
-# Download and install cloud_sql_proxy
-#
-def install_cloud_sql_proxy
-  return if defined? @cloud_sql_proxy_installed
-  puts "Installing Cloud SQL Proxy", :bold
-  Dir.chdir "/tmp" do
-    exec ["wget", "-q", "https://dl.google.com/cloudsql/cloud_sql_proxy.linux.amd64"]
-    mv "cloud_sql_proxy.linux.amd64", "/bin/cloud_sql_proxy"
-  end
-  chmod "+x", "/bin/cloud_sql_proxy"
-  mkdir "/cloudsql"
-  chmod 0777, "/cloudsql"
-  @cloud_sql_proxy_installed = true
-end
-
 ##
 # Installs the gcloud tool
 # gcloud installed from system packages https://github.com/googleapis/testing-infra-docker/pull/446