Per SDK requirement, OEM is required to support minimum number of
concurrent keepalives. Implement CTS to verify this.
Bug: 129371366
Test: atest android.net.cts
.ConnectivityManagerTest#testSocketKeepaliveLimit
--generate-new-metrics 10
Change-Id: I8be89116bed5c4dedb2ca42b6d633aa9e8c6a49a