- set default mozconfig_variant in ci/build/kind.yml
- mozconfig_variant overrides need to be moved from
mozharness/build/branch_specfics.py to ci/build/{linux,macosx,windows}.yml
- testing/mozharness/configs/builds/taskcluster_sub_win{32,64}/opt.py were
removed from M-C, need to update ci/build/windows.yml, need to move those
settings to ci/build/windows.yml
Depends on D9603
Differential Revision: https://phabricator.services.mozilla.com/D9612