Test: Refactor PrefixDiscoveryBypassTls
Remove some duplicate and unnecessary code. The test coverage should
be the same as before.
Bug: 293833962
Test: ran PrefixDiscoveryBypassTls and SetAndClearNat64Prefix together
300 times
Change-Id: Ia3a1d4a524ade93d7b35ca5b1fdd60d27b88c8ef
Loading