Fix shutil.get_terminal_size() error handling

Issue #26801: Fix error handling in shutil.get_terminal_size(), catch
AttributeError instead of NameError. Patch written by Emanuel Barry.

test_shutil: skip the functional test using "stty size" command if
os.get_terminal_size() is missing.
diff --git a/Lib/shutil.py b/Lib/shutil.py
index 3f4b6bf..7f8edf5 100644
--- a/Lib/shutil.py
+++ b/Lib/shutil.py
@@ -1069,7 +1069,7 @@
     if columns <= 0 or lines <= 0:
         try:
             size = os.get_terminal_size(sys.__stdout__.fileno())
-        except (NameError, OSError):
+        except (AttributeError, OSError):
             size = os.terminal_size(fallback)
         if columns <= 0:
             columns = size.columns