test_linux_ext_suffix performs no assertions on riscv64

Bug report

Bug description:

riscv64-unkown-linux-gnu is a PEP 11 tier platform, but test.test_sysconfig.TestSysConfig.test_linux_ext_suffix executes no assertion there.

On a debug build of main:

Python 3.16.0a0 (heads/main:8759666e4c0, Sep 17 2026, 15:27:51) [GCC 14.2.0] on linux
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>>> import sysconfig, platform
>>> platform.machine()
'riscv64'
>>> sysconfig.get_config_var('EXT_SUFFIX')
'.cpython-316d-riscv64-linux-gnu.so'
>>>

CPython versions tested on:

CPython main branch, 3.16

Operating systems tested on:

Linux

Linked PRs

• gh-157690