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: distlib
  version: 0.3.4
  top-level:
    - distlib
source:
  sha256: 6564fe0a8f51e734df6333d08b8b94d4ea8ee6b99b5ed50613f731fd4089f34b
  url: https://files.pythonhosted.org/packages/ac/a3/8ee4f54d5f12e16eeeda6b7df3dfdbda24e6cc572c86ff959a4ce110391b/distlib-0.3.4-py2.py3-none-any.whl
build:
  post: |
    find build/distlib-0.3.4/dist -name '*.exe' -delete
about:
  home: https://github.com/pypa/distlib
  PyPI: https://pypi.org/project/distlib
  summary: Distribution utilities
  license: Python license

package:
  name: distlib
  version: 0.3.4
  top-level:
    - distlib
source:
  sha256: 6564fe0a8f51e734df6333d08b8b94d4ea8ee6b99b5ed50613f731fd4089f34b
  url: https://files.pythonhosted.org/packages/ac/a3/8ee4f54d5f12e16eeeda6b7df3dfdbda24e6cc572c86ff959a4ce110391b/distlib-0.3.4-py2.py3-none-any.whl
build:
  post: |
    find build/distlib-0.3.4/dist -name '*.exe' -delete
about:
  home: https://github.com/pypa/distlib
  PyPI: https://pypi.org/project/distlib
  summary: Distribution utilities
  license: Python license
