Move Stopwatch to libnetdutils

Move Stopwatch to libnetdutils as it is an useful utility across
netd and the resolver library.

Bug: 128662167
Test: system/netd/tests/runtests.sh passed

Change-Id: Iebaffc66202fbe3a787ca645847762af1ed94bd7
diff --git a/tests/benchmarks/connect_benchmark.cpp b/tests/benchmarks/connect_benchmark.cpp
index c8d3797..e08fb01 100644
--- a/tests/benchmarks/connect_benchmark.cpp
+++ b/tests/benchmarks/connect_benchmark.cpp
@@ -70,13 +70,14 @@
 #include <android-base/stringprintf.h>
 #include <benchmark/benchmark.h>
 #include <log/log.h>
+#include <netdutils/Stopwatch.h>
 #include <utils/StrongPointer.h>
 
 #include "FwmarkClient.h"
 #include "SockDiag.h"
-#include "Stopwatch.h"
 
 using android::base::StringPrintf;
+using android::netdutils::Stopwatch;
 
 static int bindAndListen(int s) {
     sockaddr_in6 sin6 = { .sin6_family = AF_INET6 };