These were formerly used when submitting job data using the Python client
(support for which was removed in bug 1349182), and in `buildapi.py` as
part of buildbot ingestion (until #4087 / bug 1443251).
This removes the final usages in our tests so we can drop them entirely.
Since the `request` package's `iter_lines()` returns bytes by default.
We cannot pass `decode_unicode=True` to `iter_lines()` since it splits on
Unicode newlines (which can exist in test message output), so instead we
manually `.decode()` each line before parsing it.
Fixes the following exception under Python 3:
`TypeError: a bytes-like object is required, not 'str'`
The test utility `load_exp()` had to be modified to no longer use append
mode when opening the expected output JSON files, in order to fix:
`json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)`
Now that autophone and AWFY have migrated to Taskcluster, there are
no more submitters of jobs to the REST API (confirmed via New Relic
Insights). As such, this deprecated data ingestion method can now be
removed, along with support for API Hawk auth, API POST throttling
and `treeherder-client` job submission capability.
After this lands we'll need to manually drop the `credentials` table.
Ed Morley