Add thread information to format string in logs.py.
Add thread information to format string in logs.py.

This is useful if several threads are running.

BUG=364533

Review URL: https://codereview.chromium.org/1022533002

nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra,nicko96/Chrome-Infra