[#22101] DocDB: Don't set TEST_SetOutboundIpBase twice

Summary:
e6bb62a/D34307 introduced a TSAN race.

Setting TEST_SetOutboundIpBase from the test causing a TSAN race.
This function is not required to be called anymore from `TEST_SetupConnectivity` since the server sets the OutboundIpBase on its messenger as part of process startup.

Fixes #22101
Jira: DB-11034

Test Plan:
Jenkins Ready
Jenkins Urgent

Reviewers: esheng, asrivastava

Reviewed By: esheng

Subscribers: ybase

Differential Revision: https://phorge.dev.yugabyte.com/D34394

src/yb/server/server_base.cc

@@ -776,8 +776,6 @@ void TEST_SetupConnectivity(rpc::Messenger* messenger, size_t index) {
   CHECK_GE(index, kMinServerIdx);
   CHECK_LE(index, kMaxServers);
 
-  messenger->TEST_SetOutboundIpBase(
-      CHECK_RESULT(HostToAddress(TEST_RpcAddress(index, Private::kTrue))));
   auto server_group = ServerGroupNum(index);
   for (int other_server_idx = kMinServerIdx; other_server_idx <= kMaxServers; ++other_server_idx) {
     // We group servers by 2. When servers belongs to the same group, they should use