`full`: improve error handling and error messages. (#9564)
This PR refactors the `tensor_methods::full` and
`tensor_methods::full_symint` implementation by improving their error
message, and returning a status type value.
**Key Changes:**
- Make `tensor_methods::full` and `tensor_methods::full_symint` return
`StatusOr<absl_nonnull XLATensorPtr>`
- Improve error message on invalid arguments
