This was found with test-i386.  The issue is that instructions
such as

    addr32 lea (%eax), %rax

did not perform a 32-bit extension, because the LEA translation
skipped the gen_lea_v_seg step.  That step does not just add
segments, it also takes care of extending from address size to
pointer size.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>