CVE-2026-72401: bpf: Fix insn_aux_data leak on verifier err_free_env path

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix insnauxdata leak on verifier errfreeenv path

When bpfcheck() allocates env->insnauxdata successfully but later fails to allocate env->succ, it jumps directly to errfreeenv.

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

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