[PR#482] - Update ARP cache from gratuitous ARP packets v2 (FreeRTOS#974

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* Let the TCP timer becomes expired in stead of active

* Renamed parameter of function vIPSetTCPTimerExpiredState

* Adapt unit tests to use the new name and field

* Change bActive to bExpired

* Empty commit

* Fix spell check

* When a gratuitous ARP is received, use it to update the ARP cache entry

* wip

* adding comments on matching endpoint for Gratuitous ARP

* adding unit tests for Gratuitous ARP processing, fix formatting

* fix build

* fix formatting

* fix formatting

* fic CBMC

* adding review changes

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Co-authored-by: Hein Tibosch <hein@htibosch.net>
Co-authored-by: Hein Tibosch <hein_tibosch@yahoo.es>
Co-authored-by: Aniruddha Kanhere <60444055+AniruddhaKanhere@users.noreply.github.com>