Python: Descriptor tests fixup (2/3)

Test format improved

python/ql/test/library-tests/descriptors/Properties.expected

@@ -1 +1,2 @@
-| 3 | Property f | 4 | Function f | 8 | Function f |
+| test.py:4:5:4:16 | Function f | getter | test.py:3:6:3:13 | Property f |
+| test.py:8:5:8:23 | Function f | setter | test.py:3:6:3:13 | Property f |

python/ql/test/library-tests/descriptors/Properties.ql

@@ -1,13 +1,11 @@
-
 import python
 import semmle.python.types.Descriptors
 
-int lineof(Object o) {
-    result = o.getOrigin().getLocation().getStartLine()
-}
-
-from PropertyObject p, FunctionObject getter, FunctionObject setter
+from PropertyObject p, string method_name, FunctionObject method
 where
-getter = p.getGetter() and setter = p.getSetter()
-select lineof(p), p.toString(), lineof(getter), getter.toString(), lineof(setter), setter.toString()
-
+    method_name = "getter" and method = p.getGetter()
+    or
+    method_name = "setter" and method = p.getSetter()
+    or
+    method_name = "deleter" and method = p.getDeleter()
+select method, method_name, p