When running a swift_package_tests.yaml workflow, workflows running in a
docker container on windows would often fails as the docker engine was
not currently ready to accept requests.

Add a step that ensure the docker engine is started and ready, by
calling `docker info` command before performing any other docker steps
to ensure the engine is ready.

Adds a new freebsd-build job using vmactions/freebsd-vm to run Swift
builds and tests inside a FreeBSD VM on Ubuntu runners. Configurable
via freebsd_swift_versions, freebsd_os_versions, freebsd_host_archs,
freebsd_pre_build_command, freebsd_build_command, freebsd_env_vars,
and enable_freebsd_checks inputs. Supports cross-PR testing, nightly
flag selection, and multi-arch runner selection matching the existing
Linux job pattern.