ruby: Set up Ruby regression tests.

tests/SConscript

@@ -265,6 +265,9 @@ else:
     configs += ['simple-atomic', 'simple-timing', 'o3-timing', 'memtest',
                 'simple-atomic-mp', 'simple-timing-mp', 'o3-timing-mp']
 
+# Hack for Ruby
+configs += [c + '-ruby' for c in configs]
+
 cwd = os.getcwd()
 os.chdir(str(Dir('.').srcdir))
 for config in configs: