fix: immediately exit travis on build error (#2626)

.travis.yml

@@ -35,15 +35,14 @@ before_install:
     sleep 3;
   fi
 
-script:
+before_script:
+- npm run build
 - npm run forceprettier
 - if [[ $(git diff-index HEAD -- *.js *.ts) ]]; then
     git diff;
     echo "Prettier Failed. Run `gulp` or `gulp forceprettier`";
     exit 1;
   fi
-- npm run build
-- npm test --silent;
 
 before_deploy:
 - npm install -g vsce;