Honor xlat styles when decoding ioprio_get and ioprio_set

Honor xlat styles when decoding ioprio_get and ioprio_set

* ioprio.c (SYS_FUNC(ioprio_get), SYS_FUNC(ioprio_set)): Add xlat_style
support.
* tests/ioprio-Xabbrev.c: New file.
* tests/ioprio-Xraw.c: Likewise.
* tests/ioprio-Xverbose.c: Likewise.
* tests/ioprio.c: Handle XLAT_RAW, XLAT_ABBREV, and XLAT_VERBOSE macros.
* tests/gen_tests.in (ioprio-Xabbrev, ioprio-Xraw, ioprio-Xverbose): New
tests.
* tests/pure_executables.list: Add ioprio-Xabbrev, ioprio-Xraw, and
ioprio-Xverbose.
* tests/.gitignore: Likewise.

Co-Authored-by: Dmitry V. Levin <ldv@altlinux.org>