Switch ruby-hello-world test to use the common "run-ruby-in-container.sh" helper

test/tests/ruby-hello-world/run.sh

@@ -1,8 +0,0 @@
-#!/bin/bash
-set -e
-
-image="$1"
-dirTest="$(dirname "$(readlink -f "$BASH_SOURCE")")"
-dirContainer='/usr/src/ruby'
-
-docker run --rm -v "$dirTest":"$dirContainer":ro -w "$dirContainer" "$image" ruby hello-world.rb

test/tests/ruby-hello-world/run.sh

@@ -0,0 +1 @@
+../run-ruby-in-container.sh