Run core tests in Safari. Partially addresses https://github.com/pyodide/pyodide/issues/989

It runs, but there are several test failures, I'll open separate issues about those.
package:
  name: msgpack
  version: 1.0.4
  top-level:
    - msgpack
source:
  sha256: f5d869c18f030202eb412f08b28d2afeea553d6613aee89e200d7aca7ef01f5f
  url: https://files.pythonhosted.org/packages/22/44/0829b19ac243211d1d2bd759999aa92196c546518b0be91de9cacc98122a/msgpack-1.0.4.tar.gz
about:
  home: https://msgpack.org/
  PyPI: https://pypi.org/project/msgpack
  summary: MessagePack serializer
  license: Apache 2.0

package:
  name: msgpack
  version: 1.0.4
  top-level:
    - msgpack
source:
  sha256: f5d869c18f030202eb412f08b28d2afeea553d6613aee89e200d7aca7ef01f5f
  url: https://files.pythonhosted.org/packages/22/44/0829b19ac243211d1d2bd759999aa92196c546518b0be91de9cacc98122a/msgpack-1.0.4.tar.gz
about:
  home: https://msgpack.org/
  PyPI: https://pypi.org/project/msgpack
  summary: MessagePack serializer
  license: Apache 2.0
