Add back tethering to TEST_MAPPING

Tethering was removed from test mapping during S development
in some branches, but needs to be part of mainline-test-mapping
testing.

Change-Id: I440e9ae1aa958addab1c53b441e5e9e87a6d757d
Ignore-AOSP-First: Fixes difference with AOSP
Bug: 196755836
Test: TH needs to test TEST_MAPPING config
diff --git a/TEST_MAPPING b/TEST_MAPPING
index 0ac09cc..be0e040 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -29,8 +29,7 @@
   ],
   "mainline-presubmit": [
     {
-      // TODO: add back the tethering modules when updatable in this branch
-      "name": "CtsNetTestCasesLatestSdk[CaptivePortalLoginGoogle.apk+NetworkStackGoogle.apk+com.google.android.resolv.apex]",
+      "name": "CtsNetTestCasesLatestSdk[CaptivePortalLoginGoogle.apk+NetworkStackGoogle.apk+com.google.android.resolv.apex+com.google.android.tethering.apex]",
       "options": [
         {
           "exclude-annotation": "com.android.testutils.SkipPresubmit"