Remove Travis CI s390x for now to avoid hang during ant test

Author: odaira

.travis.yml

@@ -60,25 +60,6 @@ jobs:
         - ./apache-ant-1.10.6/bin/ant clean
         - ./apache-ant-1.10.6/bin/ant test-skip-jni
 
-    - name: Linux test (s390x)
-      os: linux
-      arch: s390x
-      jdk:
-        - openjdk8
-      install:
-        - wget https://github.com/lz4/lz4/archive/v1.9.2.tar.gz
-        - tar xzvf v1.9.2.tar.gz
-        - pushd lz4-1.9.2 && make && sudo make install && popd
-        - wget http://apache.osuosl.org/ant/binaries/apache-ant-1.10.6-bin.tar.gz
-        - tar xvzf apache-ant-1.10.6-bin.tar.gz
-        - ./apache-ant-1.10.6/bin/ant ivy-bootstrap
-        - ./apache-ant-1.10.6/bin/ant init
-      script:
-        - ./apache-ant-1.10.6/bin/ant dist
-        - ./apache-ant-1.10.6/bin/ant test
-        - ./apache-ant-1.10.6/bin/ant clean
-        - ./apache-ant-1.10.6/bin/ant test-skip-jni
-
     - name: macOS test
       os: osx
       osx_image: xcode9.3