* Add network down test in prvIPTask
* Align IP test configurations
* Remove redundant define check
* Fix unit test cases
* Fix stubs in some UT
* Add test cases for DHCPv6 and backward compatible
* Add test cases for FreeRTOS_GetUDPPayloadBuffer_Multi IPv6
* Test case for FreeRTOS_IPInit_Multi
* FreeRTOS_ReleaseUDPPayloadBuffer
* FreeRTOS_GetEndPointConfiguration
* FreeRTOS_GetAddressConfiguration
* FreeRTOS_GetEndPointConfiguration
* FreeRTOS_SetEndPointConfiguration
* FreeRTOS_GetAddressConfiguration
* Fix UT
* eConsiderFrameForProcessing
* prvProcessIPPacket
* vReturnEthernetFrame
* FreeRTOS_GetIPAddress
* Move IPv4 test under IPv4.
* Move IPv4 unit test cases from IP folders to IPv4 folders.
* prvProcessIPPacket
* vReturnEthernetFrame
* FreeRTOS_GetIPAddress
* FreeRTOS_IsNetworkUp
* FreeRTOS_AllEndPointsUp
* uxIPHeaderSizeSocket
* IP coverage
* FreeRTOS_SetIPAddress
* FreeRTOS_GetGatewayAddress
* FreeRTOS_GetDNSServerAddress
* FreeRTOS_GetNetmask
* FreeRTOS_UpdateMACAddress
* FreeRTOS_GetMACAddress
* FreeRTOS_SetNetmask
* FreeRTOS_SetGatewayAddress
* FreeRTOS_GetUDPPayloadBuffer_Multi
* IP coverage
* Code beautify
* prvAllowIPPacketIPv4
* prvCheckIP4HeaderOptions
* Remove legacy ipLOCAL_IP_ADDRESS_POINTER
* Add descriptions for IP test cases
* Remove redundant includes in test files.
* Add test description for IPv4 unit test
* Remove unnecessary config change
* Code beautify.
* Spelling
* Fix UT
