TetheringTester: Extend PACKET_READ_TIMEOUT_MS from 100ms to 500ms

No DHCPACK received in DHCP process. Because previous DISCOVER/OFFER
steps have done, it implies that DHCP server is launched and
client/server can transmit data to each other. Assume that DHCP server
can reply DHCPACK and CF may need more than 100ms.

Extend the timeout from 100ms to 500ms. Monitor if receiving DHCPACK
timeout is found.

Bug: 243314243
Test: atest EthernetTetheringTest
Change-Id: Id8bb0e03ae1e853beb6242a1c35b977ace9ca190
diff --git a/Tethering/tests/integration/src/android/net/TetheringTester.java b/Tethering/tests/integration/src/android/net/TetheringTester.java
index 48a406c..9cc2e49 100644
--- a/Tethering/tests/integration/src/android/net/TetheringTester.java
+++ b/Tethering/tests/integration/src/android/net/TetheringTester.java
@@ -86,7 +86,7 @@
  */
 public final class TetheringTester {
     private static final String TAG = TetheringTester.class.getSimpleName();
-    private static final int PACKET_READ_TIMEOUT_MS = 100;
+    private static final int PACKET_READ_TIMEOUT_MS = 500;
     private static final int DHCP_DISCOVER_ATTEMPTS = 10;
     private static final int READ_RA_ATTEMPTS = 10;
     private static final byte[] DHCP_REQUESTED_PARAMS = new byte[] {