Chore/test runner improvements (#12439)

**What**
Make sure there is no open handles left and that the shutdown function are properly called. Refactor and improve the medusa test runner. Make sure all modules instances are released and cleaned up

**NOTE:**
On a separate PR we can continue the investigation for the memory growing over time while the tests execute

packages/modules/index/src/services/data-synchronizer.ts

@@ -328,7 +328,7 @@ export class DataSynchronizer {
         break
       }
 
-      await setTimeout(0)
+      await setTimeout(0, undefined, { ref: false })
     }
 
     let acknoledgement: { lastCursor: string; done?: boolean; err?: Error } = {