Make FutureIter_close use Py_CLEAR directly

This just gets rid of any confusion about why FutureIter_clear is
using a critical section

Author: msullivan

Modules/_asynciomodule.c

@@ -1954,21 +1954,22 @@ FutureIter_throw(PyObject *op, PyObject *const *args, Py_ssize_t nargs)
     return NULL;
 }
 
-static int
-FutureIter_clear(PyObject *op)
+static PyObject *
+FutureIter_close(PyObject *self, PyObject *arg)
 {
-    futureiterobject *it = (futureiterobject*)op;
-    Py_BEGIN_CRITICAL_SECTION(op);
+    futureiterobject *it = (futureiterobject*)self;
+    Py_BEGIN_CRITICAL_SECTION(self);
     Py_CLEAR(it->future);
     Py_END_CRITICAL_SECTION();
-    return 0;
+    Py_RETURN_NONE;
 }
 
-static PyObject *
-FutureIter_close(PyObject *self, PyObject *arg)
+static int
+FutureIter_clear(PyObject *op)
 {
-    (void)FutureIter_clear(self);
-    Py_RETURN_NONE;
+    futureiterobject *it = (futureiterobject*)op;
+    Py_CLEAR(it->future);
+    return 0;
 }
 
 static int