Invoke tcpdump with -l

Currently ConnectivityDiagnosticsCollector invokes tcpdump with -U,
which would causes the collector failed to log ending packets due to
packet buffering.

Test:
android.net.cts.TrafficStatsTest#testTrafficStatsForLocalhost
Bug: 393471251
Change-Id: Ibe2977097bdeeef9546ce9c83b1dfd695c31f6d1
1 file changed