fix: attach to process's exit event on correct place (#671)

Author: Fatme

Diff for: lib/before-watch.js

@@ -12,10 +12,10 @@ module.exports = function ($logger, $liveSyncService, $devicesService, hookArgs)
                         stopWebpackCompiler(platform);
                     }
                 });
+            });
 
-                process.on("exit", () => {
-                    stopWebpackCompiler();
-                });
+            process.on("exit", () => {
+                stopWebpackCompiler();
             });
 
             const platforms = hookArgs.config.platforms;