bpf: Fix insn_aux_data leak on verifier err_free_env path

bpf: Fix insn_aux_data leak on verifier err_free_env path

When bpf_check() allocates env->insn_aux_data successfully but later
fails to allocate env->succ, it jumps directly to err_free_env.

The existing vfree(env->insn_aux_data) sits before the err_free_env
label, so that direct jump bypasses it and leaks insn_aux_data.

Move vfree(env->insn_aux_data) into err_free_env so all early and late
exit paths release it consistently.

Fixes: 2f69c5685427 ("bpf: make bpf_insn_successors to return a pointer")
Signed-off-by: KaFai Wan <kafai.wan@linux.dev>
Reviewed-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20260624123536.114757-1-kafai.wan@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>