selftests/bpf: validate that tail call invalidates packet pointers

Add a test case with a tail call done from a global sub-program. Such
tails calls should be considered as invalidating packet pointers.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20241210041100.1898468-9-eddyz87@gmail.com


Signed-off-by: Alexei Starovoitov <ast@kernel.org>