This matrix entry fails reliably on Xcode 9.3

Author: mxcl

.travis.yml

@@ -18,8 +18,10 @@ matrix:
     - {osx_image: xcode9.2,   env: 'PLAT=iOS     SWFT=4.0 DST="OS=11.2,name=iPhone SE"'}
     - {osx_image: xcode9.2,   env: 'PLAT=tvOS    SWFT=4.0 DST="OS=11.2,name=Apple TV"'}
 
+    # This variant fails reliably with Xcode 9.3, so sticking to Xcode 9.2 for now
+    - {osx_image: xcode9.2,   env: 'PLAT=iOS     SWFT=4.0 DST="OS=8.4,name=iPhone 4s"'}
+
     - {osx_image: xcode9.3,   env: 'PLAT=macOS   SWFT=4.1 DST="arch=x86_64"'}
-    - {osx_image: xcode9.3,   env: 'PLAT=iOS     SWFT=4.1 DST="OS=8.4,name=iPhone 4s"'}
     - {osx_image: xcode9.3,   env: 'PLAT=iOS     SWFT=4.1 DST="OS=9.3,name=iPhone SE"'}
     - {osx_image: xcode9.3,   env: 'PLAT=iOS     SWFT=4.1 DST="OS=10.3.1,name=iPhone SE"'}
     - {osx_image: xcode9.3,   env: 'PLAT=iOS     SWFT=4.1 DST="OS=11.2,name=iPhone SE"'}