add stream back

Author: Feiyang1

package.json

@@ -34,7 +34,7 @@
     "test": "lerna run --concurrency 4 --stream test",
     "test:ci": "lerna run --concurrency 4 test:ci",
     "test:release": "lerna run --concurrency 4 --ignore @firebase/*-exp --ignore firebase-exp test:ci",
-    "test:exp": "lerna run --concurrency 4 --scope @firebase/*-exp --scope firebase-exp test",
+    "test:exp": "lerna run --concurrency 4 --scope @firebase/*-exp --scope firebase-exp --stream test",
     "pretest:coverage": "mkdirp coverage",
     "ci:coverage": "lcov-result-merger 'packages/**/lcov.info' 'lcov-all.info'",
     "test:coverage": "lcov-result-merger 'packages/**/lcov.info' | coveralls",