* support 0-D output and 0-D as indice in __getitem__

* fix tests

* fix inference and UT

* add unittest for setitem

* fix xpu test

* fix xpu 0-d

* fix right value is 0d and index is List/Tensor

* Hack__getitem__ from 0-d to 1-d with FLAGS_set_to_1d

* change PHI_DECLARE_xxx to DECLARE_xxx since the change not merged to 2.5

* hack 1-D tensor to Scalar

* throw warning at __getitem__, not slice_utils