fix smoketest script in windows

package.json

@@ -20,7 +20,7 @@
     "gulp": "gulp --max_old_space_size=4096",
     "7z": "7z",
     "update-grammars": "node build/npm/update-all-grammars.js",
-    "smoketest": "cd test/smoke ; mocha"
+    "smoketest": "cd test/smoke && mocha"
   },
   "dependencies": {
     "applicationinsights": "0.17.1",
@@ -132,4 +132,4 @@
     "windows-mutex": "^0.2.0",
     "fsevents": "0.3.8"
   }
-}
+}
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