bpo-38293: Allow shallow and deep copying of property objects (GH-16438)

Copying property objects results in a TypeError. Steps to reproduce:

```
>>> import copy
>>> obj = property()
>>> copy.copy(obj)
````

This affects both shallow and deep copying.
My idea for a fix is to add property objects to the list of "atomic" objects in the copy module.
These already include types like functions and type objects.

I also added property objects to the unit tests test_copy_atomic and test_deepcopy_atomic. This is my first PR, and it's highly likely I've made some mistake, so please be kind :)

https://bugs.python.org/issue38293
(cherry picked from commit 9f3fc6c5b4993f2b362263b494f84793a21aa073)

Co-authored-by: Guðni Natan Gunnarsson <1493259+GudniNatan@users.noreply.github.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/Lib/test/test_copy.py b/Lib/test/test_copy.py
index 45a6920..35f72fb 100644
--- a/Lib/test/test_copy.py
+++ b/Lib/test/test_copy.py
@@ -99,7 +99,7 @@ class TestCopy(unittest.TestCase):
                  42, 2**100, 3.14, True, False, 1j,
                  "hello", "hello\u1234", f.__code__,
                  b"world", bytes(range(256)), range(10), slice(1, 10, 2),
-                 NewStyle, Classic, max, WithMetaclass]
+                 NewStyle, Classic, max, WithMetaclass, property()]
         for x in tests:
             self.assertIs(copy.copy(x), x)
 
@@ -357,7 +357,7 @@ class TestCopy(unittest.TestCase):
             pass
         tests = [None, 42, 2**100, 3.14, True, False, 1j,
                  "hello", "hello\u1234", f.__code__,
-                 NewStyle, Classic, max]
+                 NewStyle, Classic, max, property()]
         for x in tests:
             self.assertIs(copy.deepcopy(x), x)