[3.10] bpo-25130: Add calls of gc.collect() in tests to support PyPy (GH-28005) (GH-28027)

(cherry picked from commit 2a8127cafe1d196f858a3ecabf5f1df3eebf9a12)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Lib/test/test_raise.py b/Lib/test/test_raise.py
index 57da0e1..8dc62a9 100644
--- a/Lib/test/test_raise.py
+++ b/Lib/test/test_raise.py
@@ -438,6 +438,7 @@ def f():
         f()
 
     def test_3611(self):
+        import gc
         # A re-raised exception in a __del__ caused the __context__
         # to be cleared
         class C:
@@ -451,9 +452,11 @@ def f():
             x = C()
             try:
                 try:
-                    x.x
+                    f.x
                 except AttributeError:
+                    # make x.__del__ trigger
                     del x
+                    gc.collect()  # For PyPy or other GCs.
                     raise TypeError
             except Exception as e:
                 self.assertNotEqual(e.__context__, None)