1880572 - Migrating refest to TOML

Status: UNCONFIRMED

(Testing :: General, task)

Description

[Tom Marble]

Currently refest.list manifests are evaluated in the browser
to determine if a test should be run.
(FFI https://searchfox.org/mozilla-central/source/layout/tools/reftest/runreftest.py#1023 )
For *.list manifests (except crashtest and jstestbrowser suites)
a new syntax convention should be created to represent the same
semantics in TOML such that the CI run decision can be evaluated
uniquely in Python (without starting up a browswer session).

Thus if a *.toml manifest is present (where there is currently a *.list manifest)
then read the TOML manifest and evaluate the conditions
(without starting the browser).