`PYTHON_BASIC_REPL` is not currently tested

[devdanzin]

Bug report

Bug description:

The environment variable PYTHON_BASIC_REPL is meant to make Python use the basic REPL, but this isn't currently tested to work.

CPython versions tested on:

3.13, CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-121016: Add test for PYTHON_BASIC_REPL envioronment variable #121017
• [3.13] gh-121016: Add test for PYTHON_BASIC_REPL envioronment variable (GH-121017) #121064