Refleak when some "internal modules" are imported multiple times.

Originally taken from #107577.
```python
import sys
import importlib

def foo():
 name = "_socket"
 importlib.import_module(name)
 sys.modules.pop(name)


for _ in range(4):
 foo()

./python.exe -X showrefcount example.py
[1025 refs, 653 blocks]
```
Same with `_decimal`.
```[tasklist]
### Tasks
- [ ] https://github.com/python/cpython/pull/108241
```
