reworked getOperations (decrease size of sent operations, fixe some gc issues). garbageCollectOperation now sets origin to the direct left operation, if possible

tests-lib/helper.js

@@ -30,12 +30,14 @@ export async function compareUsers (t, users) {
     await wait(100)
   }
   await flushAll(t, users)
-
-  await users[0].db.garbageCollect()
-  await users[0].db.garbageCollect()
+  await wait()
+  await flushAll(t, users)
 
   var userTypeContents = users.map(u => u.share.array._content.map(c => c.val || JSON.stringify(c.type)))
 
+  await users[0].db.garbageCollect()
+  await users[0].db.garbageCollect()
+
   // disconnect all except user 0
   await Promise.all(users.slice(1).map(async u =>
     u.disconnect()