EthernetTetheringTest: test testTetherClatTcp on S+ device

Only test testTetherClatTcp on S+ device because R device test
is blocked on b/234727688.

Bug: 234727688
Test: atest EthernetTetheringTest
Change-Id: I65a4a8c4fe13b8320b036380b9038af094ac95a5
diff --git a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
index 43aff7e..2dcf9d7 100644
--- a/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
+++ b/Tethering/tests/integration/src/android/net/EthernetTetheringTest.java
@@ -1943,7 +1943,9 @@
                 tester, false /* isClat */);
     }
 
+    // TODO: support R device. See b/234727688.
     @Test
+    @IgnoreUpTo(Build.VERSION_CODES.R)
     public void testTetherClatTcp() throws Exception {
         // CLAT only starts on IPv6 only network.
         final TetheringTester tester = initTetheringTester(toList(TEST_IP6_ADDR),