Merge branch 'migrate from bpf_prog_test_run{,_xattr}'

Delyan Kratunov says:

====================

Fairly straight-forward mechanical transformation from bpf_prog_test_run
and bpf_prog_test_run_xattr to the bpf_prog_test_run_opts goodness.

I did a fair amount of drive-by CHECK/CHECK_ATTR cleanups as well, though
certainly not everything possible. Primarily, I did not want to just change
arguments to CHECK calls, though I had to do a bit more than that
in some cases (overall, -119 CHECK calls and all CHECK_ATTR calls).

v2 -> v3:
Don't introduce CHECK_OPTS, replace CHECK/CHECK_ATTR usages we need to touch
with ASSERT_* calls instead.
Don't be prescriptive about the opts var name and keep old names where that would
minimize unnecessary code churn.
Drop _xattr-specific checks in prog_run_xattr and rename accordingly.

v1 -> v2:
Split selftests/bpf changes into two commits to appease the mailing list.
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>