Add regression test for invalid byte_size in ctypes.CField

Adds a test to ensure that creating a ctypes.CField with a byte_size
that doesn't match the underlying C type size (e.g., 2 bytes for c_byte)
correctly raises a ValueError. This test verifies the fix for gh-132470
and prevents future regressions where such mismatches could cause an abort.

Author: dura0ok

Lib/test/leakers/test_ctypes.py

@@ -1,7 +1,7 @@
 
 # Taken from Lib/test/test_ctypes/test_keeprefs.py, PointerToStructure.test().
 
-from ctypes import Structure, c_int, POINTER
+from ctypes import Structure, c_int, c_byte, POINTER, CField
 import gc
 
 def leak_inner():
@@ -13,3 +13,17 @@ class RECT(Structure):
 def leak():
     leak_inner()
     gc.collect()
+
+
+def test_invalid_byte_size_raises(self):
+    with self.assertRaises(ValueError) as cm:
+        CField(
+            name="a",
+            type=c_byte,
+            byte_size=2,  # Wrong size: c_byte is only 1 byte
+            byte_offset=2,
+            index=1,
+            _internal_use=True
+        )
+
+    self.assertIn("does not match type size", str(cm.exception))