bpo-40662: Fixed ast.get_source_segment for ast nodes that have incomplete location information (GH-20157)

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>

Lib/ast.py

@@ -332,6 +332,8 @@ def get_source_segment(source, node, *, padded=False):
     be padded with spaces to match its original position.
     """
     try:
+        if node.end_lineno is None or node.end_col_offset is None:
+            return None
         lineno = node.lineno - 1
         end_lineno = node.end_lineno - 1
         col_offset = node.col_offset