GH-87849: Fix refleak in SEND instruction. (GH-101908)

Fix refleak in SEND instruction.

Python/bytecodes.c

@@ -727,6 +727,7 @@ dummy_func(
             else {
                 assert(retval != NULL);
             }
+            Py_DECREF(v);
         }
 
         inst(SEND_GEN, (unused/1, receiver, v -- receiver)) {

Python/generated_cases.c.h

@@ -934,6 +934,7 @@
             else {
                 assert(retval != NULL);
             }
+            Py_DECREF(v);
             POKE(1, retval);
             JUMPBY(1);
             DISPATCH();