Avoid using list comprehensions in the tests.

These cause crashes due to an existing bug with subinterpreters.

Author: ZeroIntensity

Lib/test/test_interpreters/test_api.py

@@ -725,7 +725,7 @@ def task():
                 time.sleep(1)
                 os.write({w_interp}, {FINISHED!r})
 
-            threads = [threading.Thread(target=task) for _ in range(3)]
+            threads = (threading.Thread(target=task) for _ in range(3))
             for t in threads:
                 t.start()
             """)
@@ -759,7 +759,7 @@ def test_remaining_daemon_threads(self):
             def task():
                 time.sleep(3)
 
-            threads = [threading.Thread(target=task, daemon=True) for _ in range(3)]
+            threads = (threading.Thread(target=task, daemon=True) for _ in range(3))
             for t in threads:
                 t.start()
             """)

Objects/codeobject.c

@@ -1979,9 +1979,7 @@ _PyCode_CheckNoExternalState(PyCodeObject *co, _PyCode_var_counts_t *counts,
                              const char **p_errmsg)
 {
     const char *errmsg = NULL;
-    // Why is it an assumption that there can't be any hidden
-    // locals?
-    //assert(counts->locals.hidden.total == 0);
+    assert(counts->locals.hidden.total == 0);
     if (counts->numfree > 0) {  // It's a closure.
         errmsg = "closures not supported";
     }