selftests/bpf: Load struct_ops map in global_maps_resize test

selftests/bpf: Load struct_ops map in global_maps_resize test

In prog_tests/test_global_maps_resize.c, we test various use cases for
resizing global maps. Commit 7244100e0389 ("libbpf: Don't take direct
pointers into BTF data from st_ops") updated libbpf to not store pointers
to volatile BTF data, which for some users, was causing a UAF when resizing
a datasec array.

Let's ensure we have coverage for resizing datasec arrays with struct_ops
progs by also including a struct_ops map and struct_ops prog in the
test_global_map_resize skeleton. The map is automatically loaded, so we
don't need to do anything other than add it to the BPF prog being tested
to get the coverage.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240725032214.50676-1-void@manifault.com