Remove TensorMap after cg call in HSolverPW

[Cstandardlib]

Check whether it works well without post-diag TensorMap now that cg itself uses wrapped psi as Tensor input.

auto psi_tensor = ct::TensorMap(psi.get_pointer(),
                                        ct::DataTypeToEnum<T>::value,
                                        ct::DeviceTypeToEnum<ct_Device>::value,
                                        ct::TensorShape({psi.get_nbands(), psi.get_nbasis()}));
cg.diag(hpsi_func, spsi_func, psi_tensor, eigen_tensor, this->ethr_band, prec_tensor);
ct::TensorMap(psi.get_pointer(), psi_tensor, {psi.get_nbands(), psi.get_nbasis()}).sync(psi_tensor);

[Cstandardlib]

Seems that it works well without post-diag TensorMap now that cg itself uses wrapped psi as Tensor input, so it is OK to remove this TensorMap operation.

[Cstandardlib]

Tests will be made on DCU to check TensorMap issues.

[Cstandardlib]

This PR will be closed to verify that cg works well on DCU and reopened then.