testrunner.py: fix RuntimeError: dictionary size

greentest/testrunner.py

@@ -89,7 +89,7 @@ def run_many(tests, expected=None, failfast=False):
 
     if NWORKERS > 1 and toretry:
         util.log('\nWill retry %s failed tests sequentially:\n- %s\n', len(toretry), '\n- '.join(toretry))
-        for name, (cmd, kwargs, _ignore) in failed.items():
+        for name, (cmd, kwargs, _ignore) in list(failed.items()):
             if not util.run(cmd, buffer_output=False, **kwargs):
                 failed.pop(name)
                 failed_then_succeeded.append(name)