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/server/IptablesRestoreControllerTest.cpp b/server/IptablesRestoreControllerTest.cpp
index e34f644..d01d7ce 100644
--- a/server/IptablesRestoreControllerTest.cpp
+++ b/server/IptablesRestoreControllerTest.cpp
@@ -24,14 +24,14 @@
 #include <gtest/gtest.h>
 
 #define LOG_TAG "IptablesRestoreControllerTest"
-#include <log/log.h>
 #include <android-base/stringprintf.h>
 #include <android-base/strings.h>
+#include <log/log.h>
 #include <netdutils/MockSyscalls.h>
+#include <netdutils/Stopwatch.h>
 
 #include "IptablesRestoreController.h"
 #include "NetdConstants.h"
-#include "Stopwatch.h"
 #include "bpf/BpfUtils.h"
 
 #define XT_LOCK_NAME "/system/etc/xtables.lock"
@@ -41,6 +41,7 @@
 using android::base::Join;
 using android::base::StringPrintf;
 using android::netdutils::ScopedMockSyscalls;
+using android::netdutils::Stopwatch;
 using testing::Return;
 using testing::StrictMock;