BpfCoordinatorTest: renumber the test interface indices

This is a preparation to add new interface index.

Test: atest BpfCoordinatorTest
Change-Id: I758c2e7142099d74099fb8203f41ffec9b1182ee
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
index e5fe3f8..ace5f15 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
@@ -154,9 +154,9 @@
 
     private static final int INVALID_IFINDEX = 0;
     private static final int UPSTREAM_IFINDEX = 1001;
-    private static final int UPSTREAM_IFINDEX2 = 1002;
-    private static final int DOWNSTREAM_IFINDEX = 1003;
-    private static final int DOWNSTREAM_IFINDEX2 = 1004;
+    private static final int UPSTREAM_IFINDEX2 = 1003;
+    private static final int DOWNSTREAM_IFINDEX = 2001;
+    private static final int DOWNSTREAM_IFINDEX2 = 2002;
 
     private static final String UPSTREAM_IFACE = "rmnet0";
     private static final String UPSTREAM_IFACE2 = "wlan0";
@@ -2108,7 +2108,7 @@
     @Test
     public void testIpv6ForwardingRuleToString() throws Exception {
         final Ipv6ForwardingRule rule = buildTestForwardingRule(UPSTREAM_IFINDEX, NEIGH_A, MAC_A);
-        assertEquals("upstreamIfindex: 1001, downstreamIfindex: 1003, address: 2001:db8::1, "
+        assertEquals("upstreamIfindex: 1001, downstreamIfindex: 2001, address: 2001:db8::1, "
                 + "srcMac: 12:34:56:78:90:ab, dstMac: 00:00:00:00:00:0a", rule.toString());
     }