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.
from io import BytesIO
from typing import IO, Any

REPODATA_PACKAGES: dict[str, dict[str, Any]] = {}


class loadedPackages:
    @staticmethod
    def to_py():
        return {}


from urllib.request import Request, urlopen


async def fetch_bytes(url: str, kwargs: dict[str, str]) -> IO[bytes]:
    return BytesIO(urlopen(Request(url, headers=kwargs)).read())


async def fetch_string(url: str, kwargs: dict[str, str]) -> str:
    return (await fetch_bytes(url, kwargs)).read().decode()


async def loadDynlib(dynlib: str, is_shared_lib: bool) -> None:
    pass


class pyodide_js_:
    def __get__(self, attr):
        raise RuntimeError(f"Attempted to access property '{attr}' on pyodide_js dummy")


REPODATA_INFO: dict[str, str] = {}


def loadPackage(packages: str | list[str]) -> None:
    pass


__all__ = [
    "loadDynlib",
    "fetch_bytes",
    "fetch_string",
    "REPODATA_INFO",
    "REPODATA_PACKAGES",
    "loadedPackages",
    "loadPackage",
]

from io import BytesIO
from typing import IO, Any

REPODATA_PACKAGES: dict[str, dict[str, Any]] = {}


class loadedPackages:
    @staticmethod
    def to_py():
        return {}


from urllib.request import Request, urlopen


async def fetch_bytes(url: str, kwargs: dict[str, str]) -> IO[bytes]:
    return BytesIO(urlopen(Request(url, headers=kwargs)).read())


async def fetch_string(url: str, kwargs: dict[str, str]) -> str:
    return (await fetch_bytes(url, kwargs)).read().decode()


async def loadDynlib(dynlib: str, is_shared_lib: bool) -> None:
    pass


class pyodide_js_:
    def __get__(self, attr):
        raise RuntimeError(f"Attempted to access property '{attr}' on pyodide_js dummy")


REPODATA_INFO: dict[str, str] = {}


def loadPackage(packages: str | list[str]) -> None:
    pass


__all__ = [
    "loadDynlib",
    "fetch_bytes",
    "fetch_string",
    "REPODATA_INFO",
    "REPODATA_PACKAGES",
    "loadedPackages",
    "loadPackage",
]
