Otherwise some features would go untested in non-specific contexts

I did need to disable the
`gitlab_git_diff_size_limit_increase`-feature in some specs since we
depend on diffs being expandable while the file we are testing on is
smaller than the increased limit.

These two methods now handle two additional real-world possibilities:

1. `config/resque.yml` not being present
2. `config/resque.yml` being present but not containing YAML

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/34941

Don't attempt to warm the Capybara cache outside of CI

See merge request !12761

We initially started doing this because the first feature test to use
the JavaScript driver would often time out due to asset compilation on
CI. We should still do it in CI since the cost is (relatively) low, but
doing so for every local run is both tiresome and generally unnecessary,
as developer machines will be faster than most shared CI runners, and
the cost of retrying a test after a timeout is much, much lower.

Change gitlab_sign_in to sign_in

See merge request !12369

# Conflicts:
#   app/models/concerns/each_batch.rb
#   spec/models/concerns/each_batch_spec.rb

Add variables to pipelines schedules

Closes #32568

See merge request !12372