noHostRouteIpv6LinkLocalNeighborTest testcase in saineighbor.py needs to modified as per SAI standard

[kandancs]

Hi All,

As per SAI PTF (noHostRouteIpv6LinkLocalNeighborTest in saineighbor.py) testcase expectation, host route should not created for link local IPv6 address irrespective of SAI_NEIGHBOR_ENTRY_ATTR_NO_HOST_ROUTE attribute value but SAI Header mention otherwise as below

/**
 * @brief Neighbor not to be programmed as a host route entry in ASIC and
 * to be only used to setup next-hop purpose.
 *
 * Typical use-case is to set this true for neighbor with IPv6 link-local
 * addresses.
 *
 * @type bool
 * @flags CREATE_AND_SET
 * @default false
 */
SAI_NEIGHBOR_ENTRY_ATTR_NO_HOST_ROUTE,

please refer below SAI Header link: https://github.com/opencomputeproject/SAI/blob/master/inc/saineighbor.h#L83

SAI PTF testcase link: https://github.com/opencomputeproject/SAI/blob/master/ptf/saineighbor.py#L66

it looks like SAI PTF testcase not adhere to SAI Header/standard