Merge branch 'Stop using bpf_object__find_program_by_title API'

Kui-Feng Lee says:

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

bpf_object__find_program_by_title is going to be deprecated since
v0.7.  Replace all use cases with bpf_object__find_program_by_name if
possible, or use bpf_object__for_each_program to iterate over
programs, matching section names.

V3 fixes a broken test case, fexit_bpf2bpf, in selftests/bpf, using
bpf_obj__for_each_program API instead.

[v2] https://lore.kernel.org/bpf/20211211003608.2764928-1-kuifeng@fb.com/
[v1] https://lore.kernel.org/bpf/20211210190855.1369060-1-kuifeng@fb.com/T/
====================

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