selftests/bpf: Remove may_goto tests from DENYLIST.s390x

The may_goto instruction is now fully supported on s390x, including the
timed implementation, so remove the respective test from the denylist.

Signed-off-by: Ilya Leoshkevich <[email protected]>

Author: iii-i

tools/testing/selftests/bpf/DENYLIST.s390x

@@ -2,4 +2,3 @@
 # Alphabetical order
 get_stack_raw_tp                         # user_stack corrupted user stack                                             (no backchain userspace)
 stacktrace_build_id                      # compare_map_keys stackid_hmap vs. stackmap err -2 errno 2                   (?)
-verifier_iterating_callbacks