gh-101101: Fix test_code_extra to reset value for refleak test

[corona10]

• Issue: Unstable C API tier (PEP 689) #101101

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @corona10 for commit dcb4d94 🤖

If you want to schedule another build, you need to add the 🔨 test-with-refleak-buildbots label again.

[corona10]

With out this patch:

➜  cpython git:(main) ✗ ./python.exe -m test test_capi -R 3:3
Raised RLIMIT_NOFILE: 256 -> 1024
0:00:00 load avg: 3.41 Run tests sequentially
0:00:00 load avg: 3.41 [1/1] test_capi
beginning 6 repetitions
123456
.Assertion failed: (extra == NULL), function test_code_extra, file code.c, line 82.
Fatal Python error: Aborted

Current thread 0x0000000104ba8580 (most recent call first):
  File "/Users/user/oss/cpython/Lib/unittest/case.py", line 579 in _callTestMethod
  File "/Users/user/oss/cpython/Lib/unittest/case.py", line 623 in run
  File "/Users/user/oss/cpython/Lib/unittest/case.py", line 678 in __call__
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 122 in run
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 122 in run
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 122 in run
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 122 in run
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 122 in run
  File "/Users/user/oss/cpython/Lib/unittest/suite.py", line 84 in __call__
  File "/Users/user/oss/cpython/Lib/test/support/testresult.py", line 140 in run
  File "/Users/user/oss/cpython/Lib/test/support/__init__.py", line 1104 in _run_suite
  File "/Users/user/oss/cpython/Lib/test/support/__init__.py", line 1230 in run_unittest
  File "/Users/user/oss/cpython/Lib/test/libregrtest/runtest.py", line 281 in _test_module
  File "/Users/user/oss/cpython/Lib/test/libregrtest/refleak.py", line 89 in dash_R
  File "/Users/user/oss/cpython/Lib/test/libregrtest/runtest.py", line 315 in _runtest_inner2
  File "/Users/user/oss/cpython/Lib/test/libregrtest/runtest.py", line 360 in _runtest_inner
  File "/Users/user/oss/cpython/Lib/test/libregrtest/runtest.py", line 235 in _runtest
  File "/Users/user/oss/cpython/Lib/test/libregrtest/runtest.py", line 265 in runtest
  File "/Users/user/oss/cpython/Lib/test/libregrtest/main.py", line 456 in run_tests_sequential
  File "/Users/user/oss/cpython/Lib/test/libregrtest/main.py", line 574 in run_tests
  File "/Users/user/oss/cpython/Lib/test/libregrtest/main.py", line 752 in _main
  File "/Users/user/oss/cpython/Lib/test/libregrtest/main.py", line 711 in main
  File "/Users/user/oss/cpython/Lib/test/libregrtest/main.py", line 775 in main
  File "/Users/user/oss/cpython/Lib/test/__main__.py", line 2 in <module>
  File "/Users/user/oss/cpython/Lib/runpy.py", line 88 in _run_code
  File "/Users/user/oss/cpython/Lib/runpy.py", line 198 in _run_module_as_main

Extension modules: _testcapi, _testmultiphase, _testsinglephase, _testinternalcapi (total: 4)
[1]    83285 abort      ./python.exe -m test test_capi -R 3:3

[corona10]

buildbot/s390x RHEL7 Refleaks PR

Unrelated to this PR.

Issue created to: #102351

[erlend-aasland]

Small nit to make the comment slightly clearer. Perhaps also add code to assert that we could successfully revert to the initial value?

[encukou]

Ah, that's right. The test needs to clean up after itself so it can be run again.
Thank you for the fix!