Merge pyodide_py into python_stdlib.zip. ### Description

Merges pyodide_py.tar into python_stdlib.zip. This reduces the number of network requests during the initialization.

The original intention of splitting pyodide_py.tar from pyodide.asm.data was to give users an option to provide custom files (#2023), which is now available by modifying python_stdlib.zip directly. So I think there is no reason to have both python_stdlib.zip and pyodide_py.tar.

### Checklists

- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests

from sysconfig import get_config_var

from setuptools import Extension, setup

if get_config_var("SIZEOF_VOID_P") != 4:
    # pyodide_build.pypabuild will run this three times, the first time it fails
    # and the exception is caught but the second and third times it must
    # succeed.
    raise Exception(
        """
This should appear in the log exactly one time. If it appears more than once,
the Pyodide build system has misconfigured sysconfigdata (and also the build
will fail).
"""
    )

setup(
    name="fpcast-test",
    version="0.1.1",
    author="Hood Chatham",
    author_email="roberthoodchatham@gmail.com",
    description="Test function pointer casts.",
    long_description_content_type="text/markdown",
    classifiers=[
        "Programming Language :: Python :: 3",
        "License :: OSI Approved :: MIT License",
        "Operating System :: OS Independent",
    ],
    # packages=["fpcast_test"],
    ext_modules=[Extension("fpcast_test", ["fpcast-test.c"])]
    # python_requires='>=3.6',
)

from sysconfig import get_config_var

from setuptools import Extension, setup

if get_config_var("SIZEOF_VOID_P") != 4:
    # pyodide_build.pypabuild will run this three times, the first time it fails
    # and the exception is caught but the second and third times it must
    # succeed.
    raise Exception(
        """
This should appear in the log exactly one time. If it appears more than once,
the Pyodide build system has misconfigured sysconfigdata (and also the build
will fail).
"""
    )

setup(
    name="fpcast-test",
    version="0.1.1",
    author="Hood Chatham",
    author_email="roberthoodchatham@gmail.com",
    description="Test function pointer casts.",
    long_description_content_type="text/markdown",
    classifiers=[
        "Programming Language :: Python :: 3",
        "License :: OSI Approved :: MIT License",
        "Operating System :: OS Independent",
    ],
    # packages=["fpcast_test"],
    ext_modules=[Extension("fpcast_test", ["fpcast-test.c"])]
    # python_requires='>=3.6',
)
