fix pbb itag related tests

i-tagged packets will have ETH_TYPE=0x88E7. The tests are
rewritten in the same way with MPLS.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
sw test tool: improve packet diff

Signed-off-by: WATANABE Fumitaka <watanabe.fumitaka1@gmail.com>
Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
sw test tool: improve FlowStats diff

Signed-off-by: WATANABE Fumitaka <watanabe.fumitaka1@gmail.com>
Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>
sw test tool: improve MeterStats diff

Signed-off-by: WATANABE Fumitaka <watanabe.fumitaka1@gmail.com>
Signed-off-by: Yuichi Ito <ito.yuichi0@gmail.com>