patch 8.2.1559: s390x tests work again

Problem:    s390x tests work again.
Solution:   re-enable s390x tests. (James McCoy, closes #6829)

.travis.yml

@@ -212,13 +212,12 @@ jobs:
       env:
         - *normal
         - *shadowopt
-    # Temporarily disabled, always fails
+    - <<: *linux
-    #- <<: *linux
+      arch: s390x
-    #  arch: s390x
+      name: huge/gcc-s390x
-    #  name: huge/gcc-s390x
+      compiler: gcc
-    #  compiler: gcc
+      env: *linux-huge
-    #  env: *linux-huge
+      services: []
-    #  services: []
     - <<: *linux
       arch: arm64
       name: huge/gcc-arm64

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1559,
 /**/
     1558,
 /**/