Refresh time before connectivity tests

After checking that networking is available, force a time sync.

This should avoid flakes where time changes during tests, for example
for tests using test settings like test_url_expiration_time in
NetworkMonitor.

Fixes: 342489019
Test: atest
Change-Id: I0c07440679bc14dcf5cddf55fb1391d3ed76feba

staticlibs/testutils/host/com/android/testutils/ConnectivityTestTargetPreparer.kt

@@ -61,6 +61,7 @@ open class ConnectivityTestTargetPreparer : BaseTargetPreparer() {
         setUpdaterNetworkingEnabled(testInfo, enableChain = true,
                 enablePkgs = UPDATER_PKGS.associateWith { false })
         runPreparerApk(testInfo)
+        refreshTime(testInfo)
     }
 
     private fun runPreparerApk(testInfo: TestInformation) {
@@ -141,6 +142,14 @@ open class ConnectivityTestTargetPreparer : BaseTargetPreparer() {
                         .contains(":deny")
             }
 
+    private fun refreshTime(testInfo: TestInformation,) {
+        // Forces a synchronous time refresh using the network. Time is fetched synchronously but
+        // this does not guarantee that system time is updated when it returns.
+        // This avoids flakes where the system clock rolls back, for example when using test
+        // settings like test_url_expiration_time in NetworkMonitor.
+        testInfo.exec("cmd network_time_update_service force_refresh")
+    }
+
     override fun tearDown(testInfo: TestInformation, e: Throwable?) {
         if (isTearDownDisabled) return
         installer.tearDown(testInfo, e)