avoid generating dead temp cleanup code after except blocks that return/break/continue at the end

Cython/Compiler/Nodes.py

@@ -6493,6 +6493,7 @@ class ExceptClauseNode(Node):
         code.funcstate.exc_vars = exc_vars
         self.body.generate_execution_code(code)
         code.funcstate.exc_vars = old_exc_vars
+        if not self.body.is_terminator:
             for var in exc_vars:
                 code.put_decref_clear(var, py_object_type)
             code.put_goto(end_label)