[Travis] Workaround for https://github.com/travis-ci/travis-ci/issues/7580

.travis.yml

@@ -23,6 +23,8 @@ matrix:
     env: JOB=macOS-Swift3.1
     os: osx
     osx_image: xcode8.3
+    before_install:
+      - xcrun simctl delete 38C891AB-EC79-43E4-9311-6FDEB12DCF11 || true
   - script: docker run -v `pwd`:`pwd` -w `pwd` swift:3.0.2 swift test
     env: JOB=Linux-Swift3.0.2
     sudo: required