Looper: Add app and thread info to slow message log

Adding app name, thread group and main flag indicating if the specific
looper is the app's main looper to the slow delivery/dispatch log
messages.

Having the app name and main flag within the log messages makes it
possible to detect if an app's main looper delivers or dispatches
messages slowly, causing the overall app user experience to feel
sluggish. Logging the thread group allows the distinction between
foreground or background processes, whose sluggishness affects the user
experience differently.

The same information could be extracted by fetching the uid for the
logging app, and then lookup its cgroup and process. However, that can
only be done at runtime, while having the information within the logs
allows it to be read at a later date.

Bug: 326356810
Test: manual - observe slow dispatch/delivery log messages
Based-on-patch-by: Nicklas Ekstrand <nicklas.ekstrand@sonymobile.com>
Change-Id: I270b2a173ed25455c84d015cffa56edc509faa9c