test: packet_input: Do init and term just once
test: packet_input: Do init and term just once

Call init and term functions just once, instead of for each test
suite. rte_eal_init() cannot be called again in the same process once
it has successfully returned.

Signed-off-by: Jere Leppänen <14957520de8d9815e0c353a07fe23c737f0171e9@nokia.com>
Reviewed-by: Tuomas Taipale <d030d77d5671b12fc82a6b4397d4c4cdb188b540@nokia.com>

OpenFastPath/ofp,OpenFastPath/ofp,OpenFastPath/ofp,OpenFastPath/ofp