test_lazy_import: add coverage for reload() and sys.modules deletion after reification

Bug report / test coverage gap

Lib/test/test_lazy_import/__init__.py has broad lazy import coverage, but it misses two practical state-transition scenarios after reification:

1. importlib.reload() on a module that was first imported lazily and then reified.
2. Deleting sys.modules[name] after reification and then importing again.

Why this matters

These are common import-state operations and can regress subtly when lazy import behavior changes.
Adding tests helps lock in expected semantics and prevents regressions in future import machinery refactors.

Proposed change

Add two tests in test_lazy_import:

• test_reload_after_lazy_reification_keeps_single_module_object

  • Reify a lazily imported module.
  • Call importlib.reload().
  • Assert identity consistency between the binding and sys.modules[name].

• test_reimport_after_deleting_sys_modules_entry_creates_new_module

  • Reify a lazily imported module.
  • Delete sys.modules[name].
  • Verify old binding still works.
  • Re-import module and assert a new module object is cached.

Affected files

• Lib/test/test_lazy_import/__init__.py

Version

• main (3.15 development branch)

Additional notes

This is test-only; no runtime behavior change is introduced.

Linked PRs

• gh-149014

Lib/test/test_lazy_import/init.py から始めて、既存の lazy-import のカバレッジと関連するヘルパーを読みます。まず test_lazy_import テストを実行し、その後、再実体化後の reload() と sys.modules[name] を削除した後の再インポートのカバレッジを追加します。バインディングとキャッシュされたモジュールが指定された同一性の動作を維持し、削除されたエントリの再インポートによって新しいキャッシュ済みモジュールが作成されれば完了です。