Only run APF tests on physical devices

Cuttlefish does not actually implement APF, and there is no point in
general to test APF integration on virtual devices.

Test: atest ApfIntegrationTest
Change-Id: I1f0e25255d1ebcc5a6a50a42968ea1e14b5755db
diff --git a/tests/cts/net/src/android/net/cts/ApfIntegrationTest.kt b/tests/cts/net/src/android/net/cts/ApfIntegrationTest.kt
index 0e57019..a70b85e 100644
--- a/tests/cts/net/src/android/net/cts/ApfIntegrationTest.kt
+++ b/tests/cts/net/src/android/net/cts/ApfIntegrationTest.kt
@@ -40,6 +40,7 @@
 import android.system.OsConstants.SOCK_DGRAM
 import android.system.OsConstants.SOCK_NONBLOCK
 import android.util.Log
+import androidx.test.filters.RequiresDevice
 import androidx.test.platform.app.InstrumentationRegistry
 import com.android.compatibility.common.util.PropertyUtil.getVsrApiLevel
 import com.android.compatibility.common.util.SystemUtil.runShellCommand
@@ -83,6 +84,7 @@
 
 @AppModeFull(reason = "CHANGE_NETWORK_STATE permission can't be granted to instant apps")
 @RunWith(DevSdkIgnoreRunner::class)
+@RequiresDevice
 @NetworkStackModuleTest
 // ByteArray.toHexString is experimental API
 @kotlin.ExperimentalStdlibApi