Threads are sorted by:
1. unresolved & has drafts should show up first
2. then sort by file path
3. then file level comments first
4. then sort by line
5. then sort by updated time
6. then sort by id
This should avoid most of the re-arrangements
from previous sort by date solution.
The re-arrangement will still happen if you change a comment
from unresolved to resolved or vice versa
Change-Id: I2e09211d5ab3c861c2346668d6c2b64118301972
a0d86ae964