Ruby s390x now working on Travis

Author: wsfulton

.travis.yml

@@ -473,12 +473,6 @@ matrix:
       osx_image: xcode10.2
 
   allow_failures:
-    # li_std_wstring failure see https://github.com/swig/swig/pull/1803
-    - os: linux
-      arch: s390x
-      env: SWIGLANG=ruby CPP11=1
-      sudo: required
-      dist: xenial
     # Newer version of D not yet working/supported
     - compiler: gcc
       os: linux