tests/class_descriptor.py: Fix line-endings (were CRLF).

tests/basics/class_descriptor.py

-class Descriptor:
-    def __get__(self, obj, cls):
-        print(type(obj) is Main)
-        print(cls is Main)
-        return 'result'
-
-    def __set__(self, obj, val):
-        print(type(obj) is Main)
-        print(val)
-
-class Main:
-    Forward = Descriptor()
-
-m = Main()
-r = m.Forward
-if 'Descriptor' in repr(r.__class__):
-    print('SKIP')
-else:
-    print(r)
-    m.Forward = 'a'
+class Descriptor:
+    def __get__(self, obj, cls):
+        print(type(obj) is Main)
+        print(cls is Main)
+        return 'result'
+
+    def __set__(self, obj, val):
+        print(type(obj) is Main)
+        print(val)
+
+class Main:
+    Forward = Descriptor()
+
+m = Main()
+r = m.Forward
+if 'Descriptor' in repr(r.__class__):
+    print('SKIP')
+else:
+    print(r)
+    m.Forward = 'a'
+