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: pkg_1
  version: 1.0.0
source:
  sha256: deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef
  url: https://dummy-url-that-not-exists.com/pkg_1.tar.gz
requirements:
  host:
    - pkg_1_1
    - pkg_3
  run:
    - pkg_1_1
    - pkg_3
test:
  imports:
    - pkg_1

package:
  name: pkg_1
  version: 1.0.0
source:
  sha256: deadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeefdeadbeef
  url: https://dummy-url-that-not-exists.com/pkg_1.tar.gz
requirements:
  host:
    - pkg_1_1
    - pkg_3
  run:
    - pkg_1_1
    - pkg_3
test:
  imports:
    - pkg_1
