Do not upload anything when tests fail on travis. (#8065)

This used to be the logic before I made the tests portable.

.travis.yml

@@ -13,10 +13,7 @@ install:
 before_script:
   - ./dev/bots/travis_setup.sh
 script:
-  - ./bin/cache/dart-sdk/bin/dart ./dev/bots/test.dart
-  - ./dev/bots/travis_upload.sh
-after_success:
-  - (cd packages/flutter && coveralls-lcov coverage/lcov.info)
+  - (./bin/cache/dart-sdk/bin/dart ./dev/bots/test.dart && ./dev/bots/travis_upload.sh)
 cache:
   directories:
     - $HOME/.pub-cache

dev/bots/travis_upload.sh

@@ -17,3 +17,5 @@ fi
 
 # generate the API docs, upload them
 ./dev/bots/docs.sh
+
+(cd packages/flutter && coveralls-lcov coverage/lcov.info)