Set normal sync mode for accounts DB

We can't use WAL (see b/438408487#comment4) but we could try normal sync.
This is to treat ANRs and jank that were co-incident with Accounts DB doing fsync
while the app's main thread was stalled on an I/O-related blocking_function.

I came across this while doing unrelated research:
https://docs.google.com/document/d/1zZ4GJL1ISu4pja23nizOl1jFA7MJ6lCCD5nvwFf0TSQ/edit?usp=sharing&resourcekey=0-t34iS4UP-1mVhKc8W7AZxA
Thought I'd revisit this issue.
We can try ramping this flag and study the impact.

Flag: com.android.server.accounts.sqlite_sync_normal
Bug: 438408487

Change-Id: I4677c8d6c40865f935f8605183c5844b8c7407ee