Revert "cast.h return_value_policy_override _clif_automatic (#4364)"

This reverts commit 8720cf9.

Author: rwgk

include/pybind11/cast.h

@@ -1170,7 +1170,6 @@ struct return_value_policy_override<
                         void>> {
     static return_value_policy policy(return_value_policy p) {
         return !std::is_lvalue_reference<Return>::value && !std::is_pointer<Return>::value
-                       && p != return_value_policy::_clif_automatic
                    ? return_value_policy::move
                    : p;
     }

tests/CMakeLists.txt

@@ -167,7 +167,6 @@ set(PYBIND11_TEST_FILES
     test_pickling
     test_python_multiple_inheritance
     test_pytypes
-    test_return_value_policy_override
     test_sequences_and_iterators
     test_smart_ptr
     test_stl