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

Bắt đầu trong Lib/test/test_lazy_import/init.py và đọc phần coverage hiện có cho lazy-import cùng các helper liên quan. Trước tiên, chạy các test test_lazy_import, sau đó bổ sung coverage cho reload() sau khi reification và cho việc re-import sau khi xóa sys.modules[name]. Hoàn tất khi binding và module được cache giữ nguyên hành vi identity đã nêu, trong khi việc re-import sau khi xóa entry tạo ra một module mới được cache.