Sync record from SQS is not decoded sometimes

[AlexeyBarabash]

Found during brave/brave-browser#3261 investigation.

Can see missing bookmark and the message in log

[6234:6234:0318/165347.721337:INFO:CONSOLE(1112)] "Record with CRC 3aijp5 is missing parts or corrupt.", source: chrome-extension://nomlkjnggnifocmealianaaiobmebgil/extension/brave-sync/bundles/bundle.js (1112)

STR:

1. Create sync chain

2. Sync 1000 bookmarks

3. On device1 create bookmark
   title: 2759
   url
   https://www.amazon.com/s/ref=sr_pg_2?rh=i%3Aaps%2Ck%3AB00160D1XQ%7CB01E78WLCU%7CB00HR1M8KK%7CB00NHQHOZS%7CB00NHQHP3E%7CB00NHQHP2U%7CB00NHQHPFC%7CB00NHQHP9S%7CB00NHQHKF2%7CB00NHQHK1G%7CB00NHQHJZS%7CB00NHQHKFC%7CB00WHXP7LK%7CB00WHY4ADA%7CB018AIFN50%7CB018AIFN9Q%7CB018AIFLYS%7CB018AIFLSY%7CB018AIFN6Y%7CB018AIFM4C%7CB018AIFLFM%7CB018AIFR6K%7CB01E78WKEO%7CB010B4RSLI&page=2&keywords=B00160D1XQ%7CB01E78WLCU%7CB00HR1M8KK%7CB00NHQHOZS%7CB00NHQHP3E%7CB00NHQHP2U%7CB00NHQHPFC%7CB00NHQHP9S%7CB00NHQHKF2%7CB00NHQHK1G%7CB00NHQHJZS%7CB00NHQHKFC%7CB00WHXP7LK%7CB00WHY4ADA%7CB018AIFN50%7CB018AIFN9Q%7CB018AIFLYS%7CB018AIFLSY%7CB018AIFN6Y%7CB018AIFM4C%7CB018AIFLFM%7CB018AIFR6K%7CB01E78WKEO%7CB010B4RSLI&ie=UTF8&qid=1466508917

4. Expected: bookmarks is synced

5. Actual: sometimes is not synced.

How often: see that 3 of ~7 times.

[AlexeyBarabash]

While working on #306, I have found that there is a test case
testCanListNotifications
for this issue and this case is suppressed by
t.pass('empty SQS notifications/missing records, check if more than one tests are running at the same time')

probably it is for another purposes, but it it is triggered right after
Record with CRC 1lx6Hm is missing parts or corrupt message and the records count is 0.