Use an argument list in test_typing_extensions_compiles_with_opt - #786

test_typing_extensions_compiles_with_opt builds a shell command string from
sys.executable and typing_extensions.__file__ without quoting either:

subprocess.check_output(f'{sys.executable} -OO {file_path}',
                        stderr=subprocess.STDOUT,
                        shell=True)

When the checkout (or the interpreter) is under a path containing a space, the shell
splits the path and the subprocess fails for that reason alone. Because the except
clause maps any CalledProcessError to 'Module does not compile with optimize=2 (-OO flag).', the failure is indistinguishable from a real -OO compilation error —
which is the part that cost me some time before I looked at the command being run.

Replacing the string with an argument list needs no quoting and no shell.

Reproducing

On any checkout whose path contains a space (mine is on Windows, but the same applies
to /home/user/my projects/...):

$ cd src/
$ python -m unittest test_typing_extensions.AllTests.test_typing_extensions_compiles_with_opt
AssertionError: Module does not compile with optimize=2 (-OO flag).

typing_extensions compiles fine under -OO; only the test is broken.

With this change, from the same directory:

$ python -m unittest test_typing_extensions.AllTests.test_typing_extensions_compiles_with_opt
Ran 1 test in 0.265s
OK

Full suite on the same checkout: Ran 576 tests ... OK (skipped=24).

Notes

• Test-only change; no behavior change in typing_extensions itself, so I have not
  added a CHANGELOG entry — happy to add one if you would prefer.
• Disclosure: this was found and prepared with AI assistance (Claude), which is why the
  commit carries a Co-Authored-By trailer. The reproduction, the fix and the test runs
  above are real and were executed on my machine; I am happy to adjust or drop the
  trailer if it conflicts with your policy.