[ACL] Add Tunnel Next Hop redirect support

[vivekrnv]

What I did

• Add support for Tunnel Next Hop as the Redirect Action in ACL Rules
• Add a new Macro in the SAI mocking infra to clear extern mock_fns set
• Add UT's

Why I did it

How I verified it

[----------] 4 tests from AclRedirectActionTest
[ RUN      ] AclRedirectActionTest.TunnelNH
[       OK ] AclRedirectActionTest.TunnelNH (10 ms)
[ RUN      ] AclRedirectActionTest.TunnelNH_ExistingNhObject
[       OK ] AclRedirectActionTest.TunnelNH_ExistingNhObject (10 ms)
[ RUN      ] AclRedirectActionTest.TunnelNH_InvalidTunnel
[       OK ] AclRedirectActionTest.TunnelNH_InvalidTunnel (10 ms)
[ RUN      ] AclRedirectActionTest.TunnelNH_InvalidNextHop
[       OK ] AclRedirectActionTest.TunnelNH_InvalidNextHop (10 ms)
[----------] 4 tests from AclRedirectActionTest (40 ms total)

Details if related

[vivekrnv]

[----------] 15 tests from MuxRollbackTest
[ RUN      ] MuxRollbackTest.StandbyToActiveNeighborAlreadyExists
[       OK ] MuxRollbackTest.StandbyToActiveNeighborAlreadyExists (86 ms)
[ RUN      ] MuxRollbackTest.ActiveToStandbyNeighborNotFound
pure virtual method called
terminate called without an active exception
FAIL tests (exit status: 134)

Unrelated UT failure. Not seen on local machine @lolyu Are you familiar on why this might fail?

[vivekrnv]

[----------] 15 tests from MuxRollbackTest
[ RUN      ] MuxRollbackTest.StandbyToActiveNeighborAlreadyExists
[       OK ] MuxRollbackTest.StandbyToActiveNeighborAlreadyExists (86 ms)
[ RUN      ] MuxRollbackTest.ActiveToStandbyNeighborNotFound
pure virtual method called
terminate called without an active exception
FAIL tests (exit status: 134)

Unrelated UT failure. Not seen on local machine @lolyu Are you familiar on why this might fail?

NVM, interestingly only seen on bullseye environment. Fixed the problem

[prsunny]

@bingwang-ms for viz