gh-144957: Add test for lazy imports with __getattr__

[gourijain029-del]

Adds a regression test for lazy imports working with modules that use __getattr__.

The issue reported that lazy from typing import Match would fail since Match is provided by typing.__getattr__ rather than being in the module dict. Testing shows this works correctly in current main - the existing code in register_lazy_on_parent() already checks for __getattr__ and skips adding lazy import objects to those modules.

This test documents the expected behavior and prevents future regressions.

• Issue: PEP810 lazy from imports ignore module __getattr__ when reifying #144957

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[johnslavik]

Testing shows this works correctly in current main - the existing code in register_lazy_on_parent() already checks for __getattr__ and skips adding lazy import objects to those modules.

Your test doesn't pass locally for me:

❯ ./python.exe -m unittest Lib.test.test_import.test_lazy_imports
....................................................F............BAR_MODULE_LOADED
...........................
======================================================================
FAIL: test_lazy_import_with_getattr (Lib.test.test_import.test_lazy_imports.LazyImportTests.test_lazy_import_with_getattr)
Lazy imports work with module __getattr__ (gh-144957).
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/bartosz.slawecki/Python/cpython/Lib/test/test_import/test_lazy_imports.py", line 101, in test_lazy_import_with_getattr
    self.assertEqual(result.returncode, 0, result.stderr)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1 != 0 : Traceback (most recent call last):
  File "<string>", line 4, in <module>
ImportError: deferred import of 'typing.Match' raised an exception during resolution

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<string>", line 5, in <module>
    print(Match)
          ^^^^^
ImportError: cannot import name 'Match' from 'typing' (/Users/bartosz.slawecki/Python/cpython/Lib/typing.py)

Presumably there's something with CI, needs investigation.
EDIT: See #145334.

[johnslavik]

Less prone to false positives:

Suggested change

	code = textwrap.dedent("""
	import sys
	sys.set_lazy_imports("normal")
	lazy from test.test_import.data.lazy_imports.module_with_getattr import dynamic_attr
	assert dynamic_attr == "from_getattr"
	print("OK")
	""")
	result = subprocess.run(
	[sys.executable, "-c", code],
	capture_output=True,
	text=True
	)
	self.assertEqual(result.returncode, 0, result.stderr)
	self.assertIn("OK", result.stdout)
	code = textwrap.dedent("""
	import sys
	sys.set_lazy_imports("normal")
	lazy from test.test_import.data.lazy_imports.module_with_getattr import dynamic_attr
	print(repr(dynamic_attr))
	""")
	result = subprocess.run(
	[sys.executable, "-c", code],
	capture_output=True,
	text=True
	)
	self.assertEqual(result.returncode, 0, result.stderr)
	self.assertIn("'from_getattr'", result.stdout)